Merge branch 'dns_templatezone_add-fix' into 'master'

Fix for Issue #4363 - dns_templatezone_add not working

This fixes Issue #4363.

'xfer' column can not be NULL in dns_soa table. Same solution is used in interface/web/dns/dns_wizard.php file.

It also returns created dns soa id - without return value SOAPpy would fail with "SAXParseException: <unknown>:1:0: no element found". All other functions I checked do return a value.

See merge request !564