[1.0.X] Fixed #11270 -- Modified cache template tag to prevent the creation of...

[1.0.X] Fixed #11270 -- Modified cache template tag to prevent the creation of very long cache keys. Thanks to 235 for the report and patch.

Merge of r11068 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@11070 bcc190cf-cafb-0310-a4f2-bffc1f526a37