Grant artd root capabilities that it needs to perform its tasks.

artd manages profiles and compilation artifacts that belongs individual
apps, so it needs root capabilities to do so.

The meaning of the capabilities can be found in `man capabilities 7`.

Bug: 177273468
Test: adb shell pm art delete-optimized-artifacts com.google.android.youtube
Change-Id: I2ef0778929bb7f83958b743b43abe4719c81ed2e
diff --git a/artd/artd.rc b/artd/artd.rc
index de4248a..d638a30 100644
--- a/artd/artd.rc
+++ b/artd/artd.rc
@@ -19,3 +19,5 @@
     oneshot  # Prevents the service from automatically restarting each time it is stopped.
     class core
     user artd
+    group artd
+    capabilities DAC_OVERRIDE DAC_READ_SEARCH FOWNER