Fix logging statement in sql adapter

[gunthercox]

This pull request fixes a logging statement in the SQL adapter that was triggering errors. I've replaced it with an exception logging statement that has some useful functionality (It records the exception when the method is called within the scope of an except block.

Logger.exception(msg, *args, **kwargs)

Logs a message with level ERROR on this logger. The arguments are interpreted as for debug(). Exception info is added to the logging message. This method should only be called from an exception handler.

~ https://docs.python.org/3/library/logging.html#logging.Logger.exception