[1.7.x] Prevented a crash in the cursor wrappers on Oracle.

Fixed #22483 (again).

Backport of 0f85103e from master
[1.7.x] Ignored repeated calls to connection.close().

Backport of d4cc59ef from master
[1.7.x] Renamed Transifex project from django-core to django

See also http://blog.transifex.com/post/83622601443/new-teams-management-transifex
Backport of 7c24027ba from master.
[1.7.x] Fixed #22499 -- Fixed a typo in an admin_views test that caused failure on Oracle.

Backport of d238c58912 from master
[1.7.x] Made sure cursor.close() does not complain if cursor is already closed on Oracle

Refs #22483

Backport of 53d97e4fe3 from master
[1.7.x] Fixed #22498 -- constraint name was not quoted in FK creation SQL

Backport of 843613add4 from master