[GHC] #15451: Fix Git commit ID detection in worktrees

[GHC]

#15451: Fix Git commit ID detection in worktrees
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        Reporter:  hsyl20            |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Build System      |              Version:  8.4.3
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D5016
       Wiki Page:                    |
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Changes (by bgamari):

 * status:  merge => closed
 * resolution:   => fixed


Comment:

 Merged with 2a162ebac445b629b3ba6621ce81a746b5dd98d7.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15451#comment:3>
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