s3: smbd/nmbd/winbindd - fix append on trailing slash on system paths.

The xx_path() function incorrectly uses talloc_asprintf_append()
instead of talloc_asprintf() on a path that may have been modified
by the trim_string() call previously. talloc_asprintf_append()
always sticks the new text at the *end* of the allocated buffer,
not at the end of the string.

Fix bug #10538 - Daemons crashing when lock/state/cache directory parameter has a trailing slash

https://bugzilla.samba.org/show_bug.cgi?id=10538

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Sat Apr  5 13:40:30 CEST 2014 on sn-devel-104