common/rc: support gluster volume start with a slash

The format of glusterfs' TEST_DEV or SCRATCH_DEV is XXX:XXX or
XXX:/XXX, but xfstests can't accept the latter now. So change
the regular expression from "\w:\w" to ":/?", to accept more
glusterfs device format.

Signed-off-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
1 file changed