Restrict certain domain-prefs to their respective reseller

The preferences rewrite_rule_sets, ncos_levels, and sound_sets
on a domain should be restricted to ones, that have the same reseller
as the domain itself.

In addition we have to make sure, the preference view does not die,
if an invalid preference had already been selected, for example when
the respective *set/*level had been deleted or had been one, with a wrong
reseller, because of this bug, we just fixed.

Mantis: 4127