fs: dlm: Fix memory leak of object mh

There is an error return path that is not kfree'ing mh after
it has been successfully allocates.  Fix this by moving the
call to create_rcom to after the check on rc_in->rc_id check
to avoid this.

Thanks to Alexander Ahring Oder Aring for suggesting the
correct way to fix this.

Addresses-Coverity: ("Resource leak")
Fixes: a070a91c ("fs: dlm: add more midcomms hooks")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Teigland <teigland@redhat.com>