fanatic disable-fan fails without docker installed

SRU Justification:

Impact: The function which does docker config updates/tests currently does not check for the presence of the docker command itself. And while there are error messages to stderr a call to check for fan being configured for docker accidentally results in returning true.

Fix: Adding a check for the docker command being present early in the function and return an error in that case (which is a false in the is-docker-configured case). Since the function should really always fail if there is no docker present the risk of regressions should be low.

Testcase:
 - [docker is not installed]
 - fanatic enable-fan ...
 - fanatic disable-fan ...

Hello Stefan, or anyone else affected,

Accepted ubuntu-fan into zesty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/ubuntu-fan/0.12.2.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

This bug was fixed in the package ubuntu-fan - 0.12.3

---------------
ubuntu-fan (0.12.3) artful; urgency=medium

  * fanatic: Prevent error message without docker installed (LP: #1691485)
  * fanatic: Supply LXD storage if needed (LP: #1691490)
  * dep8: Add LXD auto-test

 -- Stefan Bader <email address hidden> Mon, 22 May 2017 14:02:34 +0200

Verification on Zesty/17.04:
- with ubuntu-fan=0.12.2 and no docker installed: error message on disable-fan
- after updating to ubuntu-fan=0.12.2.1, disable-fan runs without errors.

This bug was fixed in the package ubuntu-fan - 0.12.2.1

---------------
ubuntu-fan (0.12.2.1) zesty; urgency=medium

  * fanatic: Prevent error message without docker installed (LP: #1691485)
  * fanatic: Supply LXD storage if needed (LP: #1691490)
  * dep8: Add LXD auto-test

 -- Stefan Bader <email address hidden> Mon, 22 May 2017 14:01:01 +0200

The verification of the Stable Release Update for ubuntu-fan has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

Hello Stefan, or anyone else affected,

Accepted ubuntu-fan into yakkety-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/ubuntu-fan/0.12.0.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Ran the dep8 tests which would fail for the LXD test if disable-fan without docker installed would produce an error message. Both tests passed.

There seems to be an autopkgtest regression: http://autopkgtest.ubuntu.com/packages/u/ubuntu-fan/yakkety/amd64

Could someone have a look at that?

Not sure what that was. I just hit re-try this morning and it passed now.

This bug was fixed in the package ubuntu-fan - 0.12.0.2

---------------
ubuntu-fan (0.12.0.2) yakkety; urgency=medium

  * fanatic: Prevent error message without docker installed (LP: #1691485)
  * dep8: Add LXD auto-test

 -- Stefan Bader <email address hidden> Wed, 07 Jun 2017 17:48:26 +0200