[vcpkg-acquire-msys] Correct gpg-agent termination

[emptyVoid]

Adjusts termination of gpg-agent to kill only the instance spawned by pacman from vcpkg's MSYS installation.

Resolves #9427

[emptyVoid]

Build failure has nothing to do with this PR.

-- Downloading http://otl.sourceforge.net/otlv4_40451.zip...
CMake Error at scripts/cmake/vcpkg_download_distfile.cmake:99 (message):
  

  File does not have expected hash:

          File path: [ C:/vsts/_work/3/s/downloads/temp/otlv4_40451.zip ]
      Expected hash: [ add1e54fae20175461d5f09cbe324e98b6f6a3839356136811109cf3251ca96541c101816870c6cc15d7611ad6bf9d576ac8dfce4274419b30866955c5892d15 ]
        Actual hash: [ 74499b79a756c1ecc16d6bd9b277b91add55249d2e1cb65a31786e9750ff607da1222797f318954599efc5153cecee2d3a7fd1e994c09e7ddb2507c8e5ce5c55 ]

  The file may have been corrupted in transit.  This can be caused by
  proxies.  If you use a proxy, please set the HTTPS_PROXY and HTTP_PROXY
  environment variables to
  "https://user:password@your-proxy-ip-address:port/".

[ras0219]

/azp run

[azure-pipelines]

Commenter does not have sufficient privileges for PR 10928 in repo microsoft/vcpkg

[ras0219-msft]

/azp run

[azure-pipelines]

Azure Pipelines could not run because the pipeline triggers exclude this branch/path.

[emptyVoid]

The attitude Microsoft expresses towards non-Microsoft contributions really demotivates from making an effort.

Merging a later conflicting PR #11102 featuring a subset of this PR's changes -- well good job, and thanks I guess.

[heydojo]

No attitude here @emptyVoid just lots of commits and work to review in a very busy tree 🙈

Your fix looks good although I was unable to test it. I can see what it does in principle and on the face of it, is easily an improvement on what was a quick hack I pushed for a problem I didn't have the experience or the time to properly fix.
Thanks!

[JackBoosY]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[JackBoosY]

Does this PR conflict with your PR #11810?

[emptyVoid]

Yes, if merged #11810 would make this PR obsolete.

[JackBoosY]

I think we need to merge #11810 first.

[JackBoosY]

#11810 merged.

[emptyVoid]

Closing as obsolete.