update_verifier: don't pass an unused command-line argument

update_verifier is being passed the current stage of Full Disk
Encryption (FDE): "nonencrypted" or "${vold.decrypt}".  However, since
FDE is no longer supported, it's actually now always "nonencrypted"
(which is confusing because there *is* encryption, it's just not FDE).
Also, update_verifier doesn't actually do anything with this
command-line argument, and based on the git history it never has.

Therefore, let's update the service definition to just have an
"update_verifier" service that passes no command-line argument.

Bug: 208476087
Test: presubmit
Change-Id: I8b62290360401024b6888c2e9488207d878d3f67
diff --git a/update_verifier/update_verifier.rc b/update_verifier/update_verifier.rc
index 862b062..76376c8 100644
--- a/update_verifier/update_verifier.rc
+++ b/update_verifier/update_verifier.rc
@@ -1,10 +1,4 @@
-service update_verifier_nonencrypted /system/bin/update_verifier nonencrypted
-    user root
-    group cache system
-    priority -20
-    ioprio rt 0
-
-service update_verifier /system/bin/update_verifier ${vold.decrypt}
+service update_verifier /system/bin/update_verifier
     user root
     group cache system
     priority -20