Fix handling notification click intents.

The intents sent out by DownloadManager come without category.

JIRA:CYAN-756
Change-Id: Ia1fda0177467555476577c2f614a1a2e9431f31c
Merge branch 'cm-10.1' of github.com:CyanogenMod/android_packages_apps_CMUpdater into cm-10.1