Fix init.svc. property contexts entry

It should be prefix, not exact

Bug: N/A
Test: see selinux contexts of init.svc. properties
Change-Id: I3fd71c80f752773b784ddb1d7bfa9ab1854d281f
diff --git a/private/property_contexts b/private/property_contexts
index 90041e0..de81e90 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -519,7 +519,7 @@
 hal.instrumentation.enable u:object_r:exported2_default_prop:s0 exact bool
 
 # default contexts only accessible by coredomain
-init.svc. u:object_r:init_service_status_private_prop:s0 exact string
+init.svc. u:object_r:init_service_status_private_prop:s0 prefix string
 
 # vendor-init-readable init service props
 init.svc.bugreport      u:object_r:init_service_status_prop:s0 exact string