Changes to support updating location providers.

There is now only a single config value pointing
at a list of packages to get certs from. The old
system was a bit confusing.

The fused location provider also now builds
against SDK 17, and the meta data service version
tag was renamed from the overly generic "version"
to "serviceVersion".

Bug: 7242814
Change-Id: I00d27c9cbd5cc31a37bb4a98160435d15a72e19e