Drop duplicated versions in salt.modules.pkg_resource.sort_pkglist()

[eliasp]

This prevents having packages which report the same version multiple times such as

microsoft.office = ["15.0.4569.1506","15.0.4569.1506"]

Duplicated version will be dropped to a result like this:

microsoft.office = ["15.0.4569.1506"]

This is a result of software being registered in 2 places (registry + MSI) at the same time on Windows.
I implemented this in salt.modules.pkg_resource.sort_pkglist() as a general safety measure to prevent this from happening in other situations again as it lead to quite some unstable behaviour in other modules here.

[ghost]

Test Failed.

If the failures are unrelated to your code, don't stress, a core developer will know these apart.
In the future, if possible, please branch off a passing commit to avoid false positives.
Refer to this link for build results: http://jenkins.saltstack.com/job/salt-pr-build/4216/

[eliasp]

@terminalmage Thanks a lot. I tried to do it this way but failed for some reason to do so. Will update the PR.

[terminalmage]

No prob. Thanks for the PR!

[ghost]

Test FAILed.
Refer to this link for build results: http://cookingwithsalt.org/job/salt/job/pr/job/build/24761/

[ghost]

Test PASSed.
Refer to this link for build results: http://jenkins.saltstack.com/job/salt-pr-build/4218/

[ghost]

Test FAILed.
Refer to this link for build results: http://cookingwithsalt.org/job/salt/job/pr/job/build/24762/

[terminalmage]

@eliasp Is there an open bug report that this fixes?

[eliasp]

@terminalmage No, there's no bug addressing this specific issue, but right now it looks like at least #11602 might be partially affected by this.

I also remember having seen duplicated pkg versions in some other cases during the last week when running into trouble (unfortunatley no properly documented ones) - some of them might have been fixed as as sideeffect of my other recent PRs regarding win_pkg.

[terminalmage]

OK cool, I just wanted to make sure that we closed out the associated issue, if there was one. Thanks again!