[git-hook] fix pre-push hook in case of new branch

dev/git-hooks/pre-push.sh

@@ -36,7 +36,7 @@ do
         # Handle delete
         :
     else
-        if test "$remote_oid" = "$zero"
+        if test "$remote_oid" = "$empty"
         then
             # New branch, examine all commits
             range="$local_oid"