STATEMENT PARAMETERS

DESCRIPTION
===========
Audit plugin isn't recording the placeholder's values when
a Prepared statement is executed. This defies the very
purpose of the plugin since the values aren't there to be
reviewed in the audit logs.

ANALYSIS
========
There are 2 versions of functions which insert params in
case of Prepared statement. One is used to do so by
generating the expanded query (which could be written to
logs) and the other does without generating it.

Based on few condition, this is decided in the
Prepared_statement::setup_set_params() during the PREPARE
phase itself and the corresponding function is called
during EXECUTE phase.

FIX
===
Now calling the <functions>_with_log (which generates the
expanded query) in case audit plugin(s) is/are enabled.
Achieved this by calling is_global_audit_mask_set(), a
newly added function to know if even a single audit
plugin is active or not.