Change the name advertised by the context hub service.

Bring the context hub service advertised name into compliance with
the other Android services. This changes the name from
"contexthub_service" to "context".

Test: GTS tests pass.

Change-Id: I8490d60f89bdb97813e328b9ddf08270470fda76

private/service_contexts

@@ -27,7 +27,7 @@ connectivity_metrics_logger               u:object_r:connectivity_metrics_logger
 connmetrics                               u:object_r:connmetrics_service:s0
 consumer_ir                               u:object_r:consumer_ir_service:s0
 content                                   u:object_r:content_service:s0
-contexthub_service                        u:object_r:contexthub_service:s0
+contexthub                                u:object_r:contexthub_service:s0
 country_detector                          u:object_r:country_detector_service:s0
 coverage                                  u:object_r:coverage_service:s0
 cpuinfo                                   u:object_r:cpuinfo_service:s0