walker: free commit object after using the oid
walker: free commit object after using the oid

libgit2/rugged,spraints/rugged,Acidburn0zzz/rugged,Acidburn0zzz/rugged,saraid/rugged,tpickett66/rugged,libgit2/rugged,tpickett66/rugged,tpickett66/rugged,saraid/rugged,spraints/rugged,libgit2/rugged,saraid/rugged,Acidburn0zzz/rugged