[PATCH] svcrpc: gss: handle the GSS_S_CONTINUE

Kerberos context initiation is handled in a single round trip, but other
mechanisms (including spkm3) may require more, so we need to handle the
GSS_S_CONTINUE case in svcauth_gss_accept.  Send a null verifier.

Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>