Change ".application" to ".app"
Change ".application" to ".app"

As requested in bug 12922231.

GoogleCloudPlatform/appengine-guestbook-python,artificechicago/camp2016,dmolson/appengine-guestbook-python,t9nf/appengine-guestbook-python,thejeshgn/appengine-guestbook-python,adjohnson916/appengine-guestbook-python,artificechicago/camp2016,jerarl/gcp-appengine-python,wcyuan/weather-mailer,JonGal/appengine-ml-demo,thejeshgn/appengine-guestbook-python,jeffgodwyll/appengine-flask-guestbook,GoogleCloudPlatform/appengine-guestbook-python,adjohnson916/appengine-guestbook-python,t9nf/appengine-guestbook-python,JonGal/appengine-ml-demo,dmolson/appengine-guestbook-python,Romzz/appengine-guestbook-python,jerarl/gcp-appengine-python,bkeyvani/appengine-guestbook-python,jeffgodwyll/appengine-flask-guestbook,ashwini0529/appengine-guestbook-python,ashwini0529/appengine-guestbook-python,bkeyvani/appengine-guestbook-python,Romzz/appengine-guestbook-python,JackConnor/portfolio,wcyuan/weather-mailer,JackConnor/portfolio