[1.1.X] Fixed a bug preventing cursor variables from being passed as bind...

[1.1.X] Fixed a bug preventing cursor variables from being passed as bind parameters in the oracle backend. Backport of r13042 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@13043 bcc190cf-cafb-0310-a4f2-bffc1f526a37