[1.2.X] Backport of r14537 from trunk.

Fixed #11101: Rewrote the sequence reset SQL for Oracle to prevent it from performing an implicit commit that caused all fixtures to be automatically committed, causing a large number of test failures.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14538 bcc190cf-cafb-0310-a4f2-bffc1f526a37