[GHC] #5158: Update .git-ignore in all the repos

[GHC]

#5158: Update .git-ignore in all the repos
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    Reporter:  igloo             |        Owner:  igloo       
        Type:  task              |       Status:  new         
    Priority:  normal            |    Milestone:  7.2.1       
   Component:  Compiler          |      Version:  7.0.3       
    Keywords:                    |     Testcase:              
   Blockedby:                    |   Difficulty:              
          Os:  Unknown/Multiple  |     Blocking:              
Architecture:  Unknown/Multiple  |      Failure:  None/Unknown
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 Go through all the repos, making sure .git-ignore is up-to-date.

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5158>
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