Expand try/catch for DeviceConfig in AppOpsManager

Some apps, such as the shell, do not seem to be able to always access
the DeviceConfig, and get an NPE. Fail gracefully when this happens.

Test: manual
Fixes: 182907280
Change-Id: If4de34f2022c165ad8bf5a950c8a04cfd5abacc9
1 file changed