git-version-gen gets confused if a tarball is being built inside a git directory
(ie your build directory is a subdirectory of a poky clone), and ends up calling
the release 6.0-dirty.  Add a shortcut exit so if a tarball is detected it
doesn't attempt to look at the git status.

Upstream-Status: Submitted (https://bugs.freedesktop.org/show_bug.cgi?id=90936)
Signed-off-by: Ross Burton <ross.burton@intel.com>

diff --git a/git-version-gen b/git-version-gen
index 7546884..079b93e 100755
--- a/git-version-gen
+++ b/git-version-gen
@@ -84,7 +84,10 @@ then
     v=`cat $tarball_version_file` || exit 1
     case $v in
 	*$nl*) v= ;; # reject multi-line output
-	[0-9]*) ;;
+	[0-9]*)
+		echo "$v" | tr -d '\012'
+		exit 0
+		;;
 	*) v= ;;
     esac
     test -z "$v" \