Allow apexd to stop itself

apexd stops itself when it finds that it is running on a device with
flattened APEXes (i.e. ro.apex.updatable = false).

Bug: 133907211
Test: launch sdk_phone_x86_64
adb logcat -d | grep apexd | wc -l
returns 3

Change-Id: I7fa161b069aa34adb028194b55f367fe740a0cfc
diff --git a/private/property_contexts b/private/property_contexts
index dd08c32..2473cdb 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -135,6 +135,9 @@
 ctl.stop$gsid           u:object_r:ctl_gsid_prop:s0
 ctl.restart$gsid        u:object_r:ctl_gsid_prop:s0
 
+# Restrict access to stopping apexd.
+ctl.stop$apexd          u:object_r:ctl_apexd_prop:s0
+
 # NFC properties
 nfc.                    u:object_r:nfc_prop:s0