Added permissions for the dumpstate service.

- Allow dumpstate to create the dumpservice service.
- Allow System Server and Shell to find that service.
- Don't allow anyone else to create that service.
- Don't allow anyone else to find that service.

BUG: 31636879
Test: manual verification
Change-Id: I642fe873560a2b123e6bafde645467d45a5f5711
diff --git a/private/service_contexts b/private/service_contexts
index ff9305b..2055cdc 100644
--- a/private/service_contexts
+++ b/private/service_contexts
@@ -43,6 +43,7 @@
 dreams                                    u:object_r:dreams_service:s0
 drm.drmManager                            u:object_r:drmserver_service:s0
 dropbox                                   u:object_r:dropbox_service:s0
+dumpstate                                 u:object_r:dumpstate_service:s0
 ethernet                                  u:object_r:ethernet_service:s0
 fingerprint                               u:object_r:fingerprint_service:s0
 android.hardware.fingerprint.IFingerprintDaemon u:object_r:fingerprintd_service:s0