Use a static flag to enable/disable CallerInfo "geoDescription" lookup

...and disable the lookup for now, since we don't have the latest
PhoneNumberOfflineGeocoder (from the libphonenumber library) integrated
into our tree yet.

Bug: 4595580
Change-Id: I7391cbf1558b5a23eebfff6c4ad1f6363213c9a3