[bug 928901] Fixed Needs Attention filter

It should filter by updated in the last 7 days, instead of created. Otherwise, recent replies will get lost for older questions.

See https://support.mozilla.org/en-US/forums/contributors/709835?last=55969&page=2#post-55965:

"The "needs attention" tab is only showing questions where the last post was made less than 7 days ago."

tiny r?