Catch all exceptions when retrieving ComposedIconInfo

It is possible to receive a TransactionTooLargeException when
getting the composed icon info from the package manager service.
We should catch these exceptions to avoid unnecessary crashes.

For reference:
The Binder transaction buffer has a limited fixed size, currently 1Mb,
which is shared by all transactions in progress for the process.
Consequently this exception can be thrown when there are many transactions
in progress even when most of the individual transactions are of moderate size.

see http://developer.android.com/reference/android/os/TransactionTooLargeException.html
for more details.

Change-Id: I70d35dc4926125bfbef5d8c5fb8ed6d6fcdbf159
Add SET_WALLPAPER permission to SystemUI

If an exception is thrown in updateWallpaperLocked, a call to
WallpaperManager.clear() is made.  This requires the SET_WALLPAPER
permission and will throw a SecurityException if that permission
is not granted to SystemUI.

Change-Id: I61811b65dcfe8b15f0e9030f7aa6d1dc09cea351