Allow the mysql mode to be more than just TRADITIONAL

To make it easier to later move to oslo.db match there ability
to set a different mysql mode (this will default, unless configured
explicitly off/differently to TRADITIONAL).

To ensure that we retain backwards compatibility the prior existence
of 'mysql_traditional_mode' as a boolean option will by default set
the mode to TRADITIONAL, and a new configuration option 'mysql_sql_mode' can
be used to provide a secondary overriding mode that will be used
instead (incase someone wants to use something other than TRADITIONAL).

Closes-Bug: 1326568

Change-Id: Ide34c27b12c26030c8842f3f4b0fcca43ce783a7
Include the function name on internal errors

To make it easier to debug and reason about the
exception that occurred include the function name
that was called during the sessions activation in
the exception message (and associated LOG output).

Change-Id: I21f9310f78968d1e60d88b1f77be0dc629e75525
Merge "Allow the mysql mode to be more than just TRADITIONAL"
Merge "Include the function name on internal errors"