Fixed AutoYast Import() and Write()

- bnc#898659
- Imported zones were not written to the system as they were not marked as 'modified'
- Directory /etc/named.d/ was used even if it didn't exist
- The whole named.conf was rewritten from scratch as Yast thought that something has changed that file while Yast was running
My editor? I don't think this is related to my editor. These files are created by `make check`.