waf: disable-python - align ldb's wscript

waf: disable-python - align ldb's wscript

If samba is set to use a system copy of ldb, and ldb wasn't built with
python support, then no system pyldb-util will be found.  If samba is
being built without python support then pyldb-util isn not needed, so
do not bother to try and find it.

The system ldb check had to be duplicated due to the earlier commits
which changed order of ldb and pyldb-util checks, and by association
also added a dependency of pyldb-util onto ldb.  This seemed cleaner
than messing with variables.

The build configuration for pyldb-util needs to exist even if it's
not being built, so that dependency resolution can occur throughout
the rest of the samba build system -- this required dropping the higher
level conditional and using the enabled= parameter instead.

Signed-off-by: Ian Stakenvicius <axs@gentoo.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>