This directory can be safely removed.  It was removed from C Git in 75c384efb52d0e3eb1e8c2f53668b4066fe6a8d6 ("Do not create $GIT_DIR/remotes/ directory anymore") by Junio C Hamano on Dec 19 2006.  C Git hasn't made it for almost 3 years, time for JGit to stop.