remove slightly unsafe use of head

If git rev-parse somehow didn't output anything, git-annex would crash
here.

diff --git a/Command/Uninit.hs b/Command/Uninit.hs
index 1b2e8395a862152b7b14f25d155287fdeabd9bc1..a38ac9a7e604e95e245a08bc1d53ef3bc089efbd 100644 (file)
--- a/Command/Uninit.hs
+++ b/Command/Uninit.hs
@@ -79,7 +79,7 @@ checkCanUninit recordok =
        
        current_branch = 
                ifM (inRepo Git.Ref.headExists)
-                       ( Just . Git.Ref . encodeBS . Prelude.head . lines . decodeBS <$> revhead
+                       ( headMaybe . map (Git.Ref . encodeBS) . lines . decodeBS <$> revhead
                        , return Nothing
                        )
        revhead = inRepo $ Git.Command.pipeReadStrict