remove references to Gservices from LatinIME

Open-sourced platform code shouldn't refer to Gservices.  Use the
platform-standard Secure settings table instead (which we can still
push values into from the servers on google-experience devices, like
gservices), but can be populated by other mechanisms for non-ged
phones.

Change-Id: Id0b5830bfc78c1d10dc732dce46546cd09cd1422