Show apps as unavailable when on unmounted storage

This patch allows shortcuts to apps that are currently unavailable
due to being on unmounted external storage to remain on the workspace
and in folders.  The icons will be disabled and grayed out until
the external storage is mounted.

Conflicts:
	res/values/cm_strings.xml

Ticket: QRDL-991
Change-Id: I971483806b27e3a75ef0d5bb89d8dfb86f97511e
(cherry picked from commit e709bdd2)