LOG.exception() should only be used in exception handler
LOG.exception() should only be used in exception handler

When used outside of an exception handler it will print the message
and then 'None', which isn't useful at all.

Change-Id: If687a764dea4c7dc0046d7c3054318f2a751a2ea

JioCloud/oslo-incubator,JioCloud/oslo-incubator,JioCloud/oslo-incubator