docs-xml: convert smb.conf.5 build to waf

docs-xml: convert smb.conf.5 build to waf

smb.conf(5) is different from other manpages because before it is
built, it gets merged together from a number of smaller files, one
per parameter. So we first create a parameters.all.xml file that
references all these files and then include it into master smb.conf.5.xml

One small issue is how to handle generated files in WAF build
from xi:include perspective as the files are generated in bin/default/docs-xml
rather than in docs-xml. We solve this by further expanding use of XML catalogs
and rewriting virtual path http://www.samba.org/samba/smbdotconf/ to proper
location.

Both docs-xml autoconf and waf builds work correctly now.

Autobuild-User(master): Alexander Bokovoy <ab@samba.org>
Autobuild-Date(master): Mon Sep 17 14:18:31 CEST 2012 on sn-devel-104