[1.1.X] Changed last_executed_query to avoid raising exceptions on...

[1.1.X] Changed last_executed_query to avoid raising exceptions on non-utf8-encoded parameter data. 

r12737 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12738 bcc190cf-cafb-0310-a4f2-bffc1f526a37