fs: dlm: ignore unexpected non dlm opts msgs

This patch ignores unexpected RCOM_NAMES/RCOM_STATUS messages.
To be backwards compatible, those messages are not part of the new
reliable DLM OPTS encapsulation header, and have their own
retransmit handling using sequence number matching  When we get
unexpected non dlm opts messages, we should allow them and let
RCOM message handling filter them out using sequence numbers.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>