Add log.exception to get more info
Add log.exception to get more info

Also report the actual value in the log message to
help debugging later on.
Removed 'raise e' because we don't want to raise an
exception in sample() and lose the metrics after it

Change-Id: I9f9cbc492ef17a484cfefca1188d295c490d8578

sapcc/monasca-agent,sapcc/monasca-agent,sapcc/monasca-agent