Removed support for git versions older than 2.1

debian oldoldstable has 2.1, and that's what i386ancient uses. It would be
better to require git 2.2, which is needed to use adjusted branches, but
can't do that w/o losing support for some old linux kernels or a
complicated git backport.

Annex/Fixup.hs

@@ -12,7 +12,6 @@ import Git.Config
 import Types.GitConfig
 import Config.Files
 import qualified Git
-import qualified Git.BuildVersion
 import Utility.Path
 import Utility.SafeCommand
 import Utility.Directory
@@ -42,10 +41,8 @@ fixupRepo r c = do
 {- Disable git's built-in wildcard expansion, which is not wanted
  - when using it as plumbing by git-annex. -}
 disableWildcardExpansion :: Repo -> Repo
-disableWildcardExpansion r
-	| Git.BuildVersion.older "1.8.1" = r
-	| otherwise = r
-		{ gitGlobalOpts = gitGlobalOpts r ++ [Param "--literal-pathspecs"] }
+disableWildcardExpansion r = r
+	{ gitGlobalOpts = gitGlobalOpts r ++ [Param "--literal-pathspecs"] }
 
 {- Direct mode repos have core.bare=true, but are not really bare.
  - Fix up the Repo to be a non-bare repo, and arrange for git commands