test-tags: clarify test output; simplify test script a bit (issue548).
- use simpler way ('hg id') to get current changeset id
- add 'echo' statements to guide the eye when reading output
- add some more output to clarify the state of .hgtags
- drop '-d' option from every commit/tag, since run-tests.py
does this (although with a different timestamp, so changeset
ids differ)