Fix some LOG invocations and messages

LOG.xxx("Hello %s" % xyz) should be LOG.xxx("Hello %s", xyz).
This allows the logging package to skip creating the
formatted log message if the message is not going to be emitted because
of the current log level.

The change touches error, warning and info LOG messages.

Adjust test suite for the above change since LOG now uses two parameters
instead of one.

Fix grammar, add missing "." to log messages in some places.

Change-Id: I86404c34502f07ed6dbda1c82b13db888c60f074
Merge "Fix some LOG invocations and messages"