amlook: do not use the reverse mapping

It's inherently unreliable across renames and cherry-picks.

amlook

@@ -7,17 +7,6 @@
 find_commit () {
 	in= commits=
 
-	if test -z "$commits"
-	then
-		blob=$(echo "Message-Id: $1" | git hash-object --stdin)
-		commits=$(git notes --ref amlog show $blob | sed -e '/^$/d')
-	fi
-
-	if test -z "$commits"
-	then
-		commits=$(sed -ne "s|^\([0-9a-f]\{40\}\) $1|\1|p" .git/am.log)
-	fi
-
 	if test -z "$commits"
 	then
 		# I know I know there should be "notes grep" command...
@@ -27,6 +16,11 @@ find_commit () {
 		)
 	fi
 
+	if test -z "$commits"
+	then
+		commits=$(sed -ne "s|^\([0-9a-f]\{40\}\) $1|\1|p" .git/am.log)
+	fi
+
 	if test -z "$commits"
 	then
 		echo "Never applied"