This should add the software-center-agent database to the searches. This will include purchase applications.
Please note that I was not able to test this as when I run it I get a:
$ src/unity-applications-daemon bzr diff
GLib-GIO-ERROR **: Settings schema 'com.canonical.Unity.ApplicationsLens' is not installed
Trace/breakpoint trap (core dumped)
(that is unreleated to my change). Fixes: https://bugs.launchpad.net/bugs/916121. Approved by Michal Hruby.