[1.2.X] Fixed #14068 -- Corrected error handling in loaddata when an...

[1.2.X] Fixed #14068 -- Corrected error handling in loaddata when an allow_syncdb method is defined on the router. Thanks to Xavier Ordoquy for the report.

Backport of r13612 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@13613 bcc190cf-cafb-0310-a4f2-bffc1f526a37