Explicit init .rc user.

Set the user explicitly.

Bug: 276813155
Test: boot
Change-Id: I4d16b5b6ac8c0403b82992411beb1f567fdb5119
diff --git a/cmds/atrace/atrace.rc b/cmds/atrace/atrace.rc
index 6469e95..c3cf2c2 100644
--- a/cmds/atrace/atrace.rc
+++ b/cmds/atrace/atrace.rc
@@ -533,6 +533,7 @@
 
 # Run atrace with the categories written in a file
 service boottrace /system/bin/atrace --async_start -f /data/misc/boottrace/categories
+    user root
     disabled
     oneshot