logtoprocess: fix message formatting
The logtoprocess used to try formatting the message using keyword options
instead of always using the rest of the arguments. Update it to match blackbox
behavior.
Differential Revision: https://phab.mercurial-scm.org/D5180
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.