changes required by cabal-version 1.10

Extensions got renamed.

Default-Language is required. I had to put Haskell98 because there are
subtle differences between 98 and 2010 and git-annex has always been
built with the default, which was 98 when there was a default. I don't
know how to establish that git-annex will behave the same under 2010.

git-repair.cabal

@@ -39,7 +39,8 @@ source-repository head
 Executable git-repair
  Main-Is: git-repair.hs
  GHC-Options: -threaded -Wall -fno-warn-tabs
- Extensions: LambdaCase
+ Default-Language: Haskell98
+ Default-Extensions: LambdaCase
  Build-Depends: split, hslogger, directory, filepath, containers, mtl,
  unix-compat (>= 0.5), bytestring, exceptions (>= 0.6), transformers,
  base (>= 4.11.1.0 && < 5.0), IfElse, text, process, time, QuickCheck,