Multinode action ordering needs to be retained

Probably why this wasn't found was that if the deploy_ clause does have a role, the ordering is correct. Only if the deploy_* clause has no role (and therefore needs to be copied to each device) does the problem occur.

Working:
http://multinode.validation.linaro.org/scheduler/job/2344/definition

Broken:
http://multinode.validation.linaro.org/scheduler/job/2333/definition

There are two types of implementation possible for this:

Type 1: Is available in
https://code.launchpad.net/~stylesen/lava-scheduler/retain-multinode-action-ordering
 In this implementation, we preserve the order of commands within the
action list as provided by the user. If the user specifies a wrong order
in the original multinode job that will be carried on to the sub jobs
that will be created. This is the correct way, because we give the user
control to execute the commands in the way they want. For example, in
case of lava-test-shell test cases and lava-android-test test cases, if
the user prefers a particular order he/she is free to enforce that
according to this implementation.

Type 2: Conceptual and not implemented
 We could have a dictionary with all the available lava-dispatcher
commands and an associated priority with it. We can get the job json and
re-organize the commands in the order dictated by the dictionary we have
built. This approach will have the following disadvantages:
 1. User preference for command execution is not honored.
 2. The dictionary should be part of lava-dispatcher and called in
lava-scheduler. Everytime a new command is added we should juggle with
this dictionary to decide the priority which is highly error prone.
 3. We enforce a structure and stop flexibility for experimentation.

Due to the above, we have implemented "Type 1" which will be part of
lava-scheduler.

PS: Documenting here for posterity.
--
Senthil Kumaran
http://www.stylesen.org/
http://www.sasenthilkumaran.com/