aggregator doesn't check for duplicate feed before attemptint to insert new feed

aggregator.module doesn't check for duplicate feed before attemptint to insert new feed.

attempt to insert duplicate produces the error displayed on screen as noted below.

A small amount of addition code that queries for a duplicate feed name before attempting insertion of a new feed would fix the problem, I imagine.

user error: Duplicate entry 'http://news.google.com/?ned=us&topic=po&output=rss' for key 2
query: INSERT INTO aggregator_feed (fid, title, url, refresh, block) VALUES (6, 'news google most popular', 'http://news.google.com/?ned=us&topic=po&output=rss', 3600, 5) in /home/mysite/public_html/includes/database.mysql.inc on line 66.

warning: Cannot modify header information - headers already sent by (output started at /home/mysite/public_html/includes/common.inc:384) in /home/mysite/public_html/includes/common.inc on line 192.