Add SELinux properties for artd

Test: boot device and check for artd process
Change-Id: I2a161701102ecbde3e293af0346d1db0b11d4aab
diff --git a/apex/com.android.art-file_contexts b/apex/com.android.art-file_contexts
index d2a8626..2533cac 100644
--- a/apex/com.android.art-file_contexts
+++ b/apex/com.android.art-file_contexts
@@ -2,6 +2,7 @@
 # System files
 #
 (/.*)?                   u:object_r:system_file:s0
+/bin/artd                u:object_r:artd_exec:s0
 /bin/dex2oat(32|64)?     u:object_r:dex2oat_exec:s0
 /bin/dexoptanalyzer      u:object_r:dexoptanalyzer_exec:s0
 /bin/odrefresh           u:object_r:odrefresh_exec:s0