Allow update_verifier to access bootctrl_block_device.

Bug: 26039641
Change-Id: Ifd96b105f054b67f881529db3fe94718cab4a0f4
(cherry picked from commit 8eaf25856eab787d5226441b6f3032fdfef9cbb9)
diff --git a/file_contexts b/file_contexts
index 7a8d0ea..dcf0c77 100644
--- a/file_contexts
+++ b/file_contexts
@@ -187,6 +187,7 @@
 /system/bin/inputflinger u:object_r:inputflinger_exec:s0
 /system/bin/logd        u:object_r:logd_exec:s0
 /system/bin/uncrypt     u:object_r:uncrypt_exec:s0
+/system/bin/update_verifier u:object_r:update_verifier_exec:s0
 /system/bin/logwrapper  u:object_r:system_file:s0
 /system/bin/vdc         u:object_r:vdc_exec:s0
 /system/bin/install-recovery.sh u:object_r:install_recovery_exec:s0