The qpcache_findzonecut() accepts two "foundnames": 'foundname' and
'dcname' could be NULL. Originally, when 'dcname' would be NULL, the
'dcname' would be set to 'foundname'. Then code like this was present:
result = find_deepest_zonecut(&search, node, nodep, foundname,
rdataset,
sigrdataset DNS__DB_FLARG_PASS);
dns_name_copy(foundname, dcname);
Which basically means that we are copying the .ndata over itself for no
apparent reason. Cleanup the dcname vs foundname usage.
Co-authored-by: Evan Hunt <each@isc.org>
Co-authored-by: Ondřej Surý <ondrej@isc.org>