Maniphest: Fix "Needs Triage" views

Summary:
"needs triage" is a priority, not a status. I just wrote these
queries incorrectly.

Test Plan:
looked at "your -> need triage" and "all -> need triage" views,
checked query via darkconsole

Differential Revision: 39
Reviewed By: aran
Reviewers: fratrik, aran
CC: aran