Explicitly set root user for ueventd and init_debug_policy

Bug: 276813155
Test: /apex/com.android.virt/bin/vm run-microdroid
Change-Id: Iaef9086f23e1d0e717e8aa4e05035868623b98f2
diff --git a/microdroid/init.rc b/microdroid/init.rc
index 29f8970..871db94 100644
--- a/microdroid/init.rc
+++ b/microdroid/init.rc
@@ -146,6 +146,7 @@
     capabilities CHOWN DAC_OVERRIDE DAC_READ_SEARCH FOWNER SYS_ADMIN
 
 service ueventd /system/bin/ueventd
+    user root
     class core
     critical
     seclabel u:r:ueventd:s0
@@ -161,6 +162,7 @@
     setenv HOSTNAME console
 
 service init_debug_policy /system/bin/init_debug_policy
+    user root
     oneshot
     disabled
     stdio_to_kmsg