pkgs/applications/version-management/git-and-tools/git: be verbose when creating symlinks

The postInstall hook replaces identical copies of the same files in $out with
symlinks. This patch changes the call to 'ln' to pass the '-v' flag so that we
can see in the build log which files were replaced.

svn path=/nixpkgs/trunk/; revision=25455

pkgs/applications/version-management/git-and-tools/git/default.nix

@@ -121,7 +121,7 @@ stdenv.mkDerivation rec {
         if [ -z "''\${seen["$sum"]}" ]; then
           seen["$sum"]="$f"
         else
-          rm "$f"; ln -s "''\${seen["$sum"]}" "$f"
+          rm "$f"; ln -v -s "''\${seen["$sum"]}" "$f"
         fi
       done