LU-6349 idl: remove obsolete RPC MSG flags

LU-6349 idl: remove obsolete RPC MSG flags

Add comments for MSG_* flags, and delete obsolete flags
MSG_LAST_REPLAY, MSG_AT_SUPPORT, MSG_DELAY_REPLAY, MSG_VERSION_REPLAY.

Remove now-unused imp_no_lock_replay field.

Add comments for MSG_CONNECT_* flags, and delete obsolete flag
MSG_CONNECT_ASYNC.

Delete them from wirecheck files.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I4f6ba93151246d173d796a6625a683cf65f767f7
Reviewed-on: https://review.whamcloud.com/17831
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: Steve Guminski <stephenx.guminski@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>