Avoid search being done twice on primary filter

The 'changed' event is emitted when someone presses Enter on the entry. Since
we already do a search when the entry is activated, doing again when the
primary filter is changed would result in doing the same query twice.

Change-Id: Iff1fb7abf92f40f96da3a35f43576db1475bacd5
Merge "Avoid search being done twice on primary filter"