rootdir: Execute update_verifier for A/B update.

update_verifier verifies the updated partitions and marks the current
slot as having booted successfully. It needs to be triggered prior to
the start of the framework, otherwise it won't be able to fall back to
the old system without a data wipe.

Bug: 26039641
Change-Id: I6fd183cdd3dfcc72feff2a896368158875b28591
diff --git a/rootdir/init.rc b/rootdir/init.rc
index a0b1acf..99c5526 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -486,6 +486,8 @@
     class_start core
 
 on nonencrypted
+    # A/B update verifier that marks a successful boot.
+    exec - root -- /system/bin/update_verifier nonencrypted
     class_start main
     class_start late_start
 
@@ -514,9 +516,13 @@
     trigger post-fs-data
 
 on property:vold.decrypt=trigger_restart_min_framework
+    # A/B update verifier that marks a successful boot.
+    exec - root -- /system/bin/update_verifier trigger_restart_min_framework
     class_start main
 
 on property:vold.decrypt=trigger_restart_framework
+    # A/B update verifier that marks a successful boot.
+    exec - root -- /system/bin/update_verifier trigger_restart_framework
     class_start main
     class_start late_start