If the MySQL user doesn't have trigger permission, an SQLException was
thrown along with an unhelpful generic error message.  This privilege
is now checked before beginning the install/upgrade, and the message
is now informative.

Change-Id: If35750610cdc84e97bf8f2974d496dea43b8b991
Signed-off-by: Richard Mansfield <richard.mansfield@catalyst.net.nz>