s4:libcli:smb2: add the client_guid to the smbcli_options

s4:libcli:smb2: add the client_guid to the smbcli_options

and initialize it in lpcfg_smbcli_options() instead of
in smb2_transport_init() as previously.

Having the client guid in the smbcli_options will allow
us to control them from callers later.

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>