[1.3.X] Fixed #13648 - '%s' escaping support for sqlite3 regression.

Thanks to master for the report and initial patch, and salgado and others
for work on the patch.

Backport of [16209] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.3.X@16210 bcc190cf-cafb-0310-a4f2-bffc1f526a37