s3: smbd: DFS - Remove the last lp_posix_pathnames() from the SMB2/3 code paths.

s3: smbd: DFS - Remove the last lp_posix_pathnames() from the SMB2/3 code paths.

lp_posix_pathnames() is only used in one place in SMB1 DFS
processing - in dealing with buggy clients, and not at all in SMB2/3.

Note that the removal of lp_posix_pathnames() in the initial detection
of path separator is a change in behavior - but the case where an
incoming DFS name *doesn't* begin with the correct separator is a client bug,
so I'm comfortable with making this change.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
Autobuild-User(master): Uri Simchoni <uri@samba.org>
Autobuild-Date(master): Fri Mar 25 13:23:48 CET 2016 on sn-devel-144