Solaris only uses one colon in the listing of the ACL mask, Linux uses two,
so substitute egrep for grep and make the second colon optional.
The -q option for Solaris 7's /usr/xpg4/bin/egrep does not appear to be
implemented, so redirect output to /dev/null.
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>