Tests passing for a minimal --interactive implementation.

* bzrlib/tests/test_conflicts.py:
(TestResolveDuplicatePaths.test_resolve_keeping_this,
TestResolveDuplicatePaths.test_resolve_keeping_other): Use better
action names.

* bzrlib/tests/blackbox/test_conflicts.py:
(TestResolve.test_resolve_interactive): Fix failing test by
providing an exiting action.

* bzrlib/conflicts.py:
(_resolve_interactive): Minimal implementation.