[1.3.X] Fix #15880: Prevent "stalling" when running dev server in background...

[1.3.X] Fix #15880: Prevent "stalling" when running dev server in background by ignoring SIGTTOU for the duration of tcsetattr.

Backport of [16326] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.3.X@16327 bcc190cf-cafb-0310-a4f2-bffc1f526a37