Check for externally installed apps if sdcard ejected

If the SD card is ejected without being properly unmounted, it is
possible for PackageManagerService to be holding onto an app that
was currently mounted in an ASEC.  In this case
PackageHelper.getSecureContainerList() will return an empty list so
we should iterate over all the packages and any that are flagged as
being installed on external storage should be added to the list so
that those apps that were running can be killed and PackageManager
can stop holding onto the open file (apk).

Change-Id: Ie2a313a5bcf7a97d52ab04eeb51a5ec6fd1fa4cd
TICKET: CYNGNOS-903