Fix the cleanup-outdated-handlers to only delete handlers that are not present in the GS

[larohra]

Description

This PR focuses on fixing the cleanup-outdated-handlers functions to only delete handlers that are not present in the GS rather than cleaning up all the Extension Handlers with State==NotInstalled.

This PR addresses 1st part of the issue where the LinuxAgent does not report install failures properly back to CRP which leads to a bad customer experience.

Issue #

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PR information

• The title of the PR is clear and informative.
• There are a small number of commits, each of which has an informative message. This means that previously merged commits do not appear in the history of the PR. For information on cleaning up the commits in your pull request, see this page.
• Except for special cases involving multiple contributors, the PR is started from a fork of the main repository, not a branch.
• If applicable, the PR references the bug/issue that it fixes in the description.
• New Unit tests were added for the changes made and Travis.CI is passing.

Quality of Code and Contribution Guidelines

• I have read the contribution guidelines.

[codecov]

Codecov Report

Merging #1889 into develop will increase coverage by 0.24%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #1889      +/-   ##
===========================================
+ Coverage    69.20%   69.44%   +0.24%     
===========================================
  Files           83       83              
  Lines        11445    11445              
  Branches      1589     1590       +1     
===========================================
+ Hits          7920     7948      +28     
+ Misses        3202     3166      -36     
- Partials       323      331       +8     

Impacted Files	Coverage Δ
azurelinuxagent/ga/exthandlers.py	87.53% <100.00%> (-0.69%)	⬇️
azurelinuxagent/pa/provision/default.py	74.24% <0.00%> (-1.02%)	⬇️
azurelinuxagent/common/protocol/wire.py	77.00% <0.00%> (+4.86%)	⬆️

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[pgombar]

Minor comments, thanks for this change!

[narrieta]

added some minor comments