conman:  Tune logging.

Move some (but not all!) debug log messages to info log messages, and
make sure conman logs info messages by default.

Also, fix a bug which sometimes prevented the conman main loop
sleeping before running again (which substantially contributed to high
log volume).

BUG=30608525

Change-Id: I6d2c599d914238c4d1b1e73b695088fd843b38ae
2 files changed