Starts default Context Hub HAL in context_hub group

Also adds group to default sensors HAL.

Bug: 149981913
Test: Compile
Change-Id: Ib9178dd9ad0a92821cfebe82f09e8819b42a42f7
diff --git a/contexthub/1.0/default/android.hardware.contexthub@1.0-service.rc b/contexthub/1.0/default/android.hardware.contexthub@1.0-service.rc
index b659be8..fc2893f 100644
--- a/contexthub/1.0/default/android.hardware.contexthub@1.0-service.rc
+++ b/contexthub/1.0/default/android.hardware.contexthub@1.0-service.rc
@@ -1,5 +1,5 @@
 service vendor.contexthub-hal-1-0 /vendor/bin/hw/android.hardware.contexthub@1.0-service
     interface android.hardware.contexthub@1.0::IContexthub default
     class hal
-    user system
-    group system
+    user context_hub
+    group context_hub