s3: libsmb: Correctly trim a trailing \\ character in cli_smb2_create_fnum_send(...

s3: libsmb: Correctly trim a trailing \\ character in cli_smb2_create_fnum_send() when passing a pathname to SMB2 create.

We already trim any leading \\ characters in this function, so this is the simplest place
to clean the pathname.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11986

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): Wed Jun 22 10:33:29 CEST 2016 on sn-devel-144

(cherry picked from commit c0704d99ce43a5497a29bfc53331159e4f978441)