[SCSI] libfc: RNN_ID may be required before RSNN_NN with some switches

One could interpret FC-GS-5 to say that an explicit RNN_ID is required
before RSNN_NN is allowed to succeed, which is why RNN_ID was not obsoleted
along with RPN_ID acording to this document:
ftp://ftp.t11.org/t11/member/fc/gs-5/05-546v2.pdf

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>