client.net.net_utils: Fix some problems found by pylint

1) Fix undefined client_utils reference.
2) Use a less generic ImportError catchall.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
server/hosts/factory.py: Disabling undefined variable pylint error

In this particular case, the missing variables are being
injected in the code namespace. So, in order to silence
pylint (and the Pydev code analyzer), add the appropriate
comments and tags.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
database_legacy/autotest-upgrade-db: Fixing another rename mistake

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>