Fix crash if there is no back button
Don't show notification count for a notification with just one item

For example, the Play Store sets the number attribute to 1 for a single
app update. No point in showing a counter for that.

Change-Id: I818622419f4f043fa8f04339ab24744aca7c1584
un'altro test
Merge branch 'kitkat-dev' of github.com:BAM-Team/android_frameworks_base into kitkat-dev