Remove more references to GAE (#2894)

These are old/pointless now that we've migrated to GKE. Note that this
doesn't update anything in the docs/ folder, as that's a much larger
project that should be done on its own.

config/nom_build.py

@@ -104,7 +104,7 @@ PROPERTIES = [
     Property('testFilter',
              'Comma separated list of test patterns, if specified run only '
              'these.'),
-    Property('environment', 'GAE Environment for deployment and staging.'),
+    Property('environment', 'Environment for deployment and staging.'),
 
     # Cloud SQL properties
     Property('dbServer',