Don't abort typical sync on blocked template to instance connections

Don't abort typical sync on blocked template to instance connections

Currently typical synchronization has a validation step that aborts the
whole diagram synchronization if there is even a single connection
missing from the instance diagram that cannot be copied from the typical
template because another instance-specific connection has been made to
the same functional terminal where the template connection is supposed
to be connected.

This changes the synchronization to simply report these cases as
WARNINGS in the verbose synchronization log and continue the
synchronization.

gitlab #323

Change-Id: I7661f6f069666fb0e6f724e6d0006e6632f93567