Settings: fix NPE with null check on NFC adapter

Verifies the adapter is not null before dereferencing it and log and error if so

Change-Id: Id2a34c4698a97476bee9b78cb0ac7b980d1595cf
Merge "Settings: fix NPE with null check on NFC adapter" into android-4.4
Merge branch 'android-4.4' of https://github.com/omnirom/android_packages_apps_Settings into android-4.4