[DO NOT MERGE] Initiailize APP_SEARCH_IMRPOVEMENT flag outside DEBUG builds.

This is addressing a bug where flags are only changed on debug build
devices or initially when changes. When nexuslauncher restarts the flag
is no longer retrieved.

Change-Id: Ieb6f460a271c918ee4e493b34692244f39cb3740
(cherry picked from commit e1664fcf)