smbd: Fix file name buflen and padding in notify repsonse

smbd: Fix file name buflen and padding in notify repsonse

The array is uint16, doubling the file name length consumes twice the space
required.

As we're hand assembling this as a series of concatinated individual data_blobs,
we must take care to ensure the correct 4 byte alignment that was
being masked by the previous doubling of the filename length.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10634

Signed-off-by: Jeremy Allison <jra@samba.org>
Signed-off-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sun Oct 18 01:56:41 CEST 2015 on sn-devel-104