Remove .lock file on server shutdown.

This should be a minimal fix for situations
where FileMaker can't obtain a lock on the .lock
file in ManagedRepository.
Update the "No FS!" message.
Try to overtake .lock file.
Make ImportLibrary error message universal.
Don't try/catch where it's not needed.
Fix LegacyRepositoryUnitTest.java.
Add unit test for repository takeover.
Make sure to use absolute path.
Remove unnecessary try/catch/throw.
Fix LegacyRepositoryUnitTest.java.
Merge pull request #2716 from bpindelski/rebased/dev_5_0/12359_repo_lock

Acquire repository lock forcefully (fix #12359). (rebased onto dev_5_0)