Add some system packages to package list adapter.

As we're using the adapter for notification control stuff, we need to
include those packages, too, as they're throwing notifications as well.

Also optimize code a little.

Change-Id: I8829041a535923e3d93d9566e27eb99c48f25abd
(cherry picked from commit 560eab0f62391ec92939fde4cba61ace4fa653f8)
Update cm_strings.xml
(cherry picked from commit f559322188b3fc6634585c5eb6e9ee66c393ccfd)