cLock: Check NETWORK_PROVIDER before call requestSingleUpdate

Check whether the NETWORK_PROVIDER location provider is supported before
call requestSingleUpdate to avoid "null provider" exception.

Change-Id: I3be2648565a51f8592d7278ac67f70d239e37494
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
Merge branch 'cm-10.1' of github.com:CyanogenMod/android_packages_apps_LockClock into cm-10.1