Merge ~smoser/cloud-init:cleanup/tox-1.7.5 into cloud-init:master

[Scott Moser]

tests: move to using tox 1.7.5

When we moved to having tox run on tests/ and tools/ we bumped tox
to version 1.7.1. That was an error on my part as I just checked the
version I had locally and didn't go looking for what the newest upstream
release was.

The current version as of today is 1.7.5 and 'tox -e pylint' works with
this version

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:1d1c31292a0d10e3dd8940739b577fad9d18f5c5
https://jenkins.ubuntu.com/server/job/cloud-init-ci/611/
Executed test runs:
    SUCCESS: Checkout
    SUCCESS: Unit & Style Tests
    SUCCESS: Ubuntu LTS: Build
    SUCCESS: Ubuntu LTS: Integration
    SUCCESS: MAAS Compatability Testing
    IN_PROGRESS: Declarative: Post Actions

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/cloud-init-ci/611/rebuild

review: Approve (continuous-integration)

[Ryan Harper (raharper)]

review: Approve

diff --git a/tox.ini b/tox.ini
index d7316cc..0802072 100644
--- a/tox.ini
+++ b/tox.ini
@@ -24,7 +24,7 @@ setenv =
 basepython = python3
 deps =
     # requirements
-    pylint==1.7.1
+    pylint==1.7.5
     # test-requirements because unit tests are now present in cloudinit tree
     -r{toxinidir}/test-requirements.txt
 commands = {envpython} -m pylint {posargs:cloudinit tests tools}