Fix check for tags.

If there is a branch with the same name as a tag it fails without the
--tags. This was only a problem when we're branching from a git tag.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

script/release/make-branch

@@ -46,7 +46,7 @@ if [ -z "$REMOTE" ]; then
 fi
 
 # handle the difference between a branch and a tag
-if [ -z "$(git name-rev $BASE_VERSION | grep tags)" ]; then
+if [ -z "$(git name-rev --tags $BASE_VERSION | grep tags)" ]; then
     BASE_VERSION=$REMOTE/$BASE_VERSION
 fi