Tweak message length check to avoid truncation on github. Re #3977.

...and this time remember to actually change the values that are used
in the check.

.githooks/commit-msg

@@ -62,12 +62,12 @@ msg_first() {
 	if test $len -eq 0; then
 		# not yet first line
 		return
-	elif test $len -lt 30; then
-		die 'The first line should be at least 25 characters (yours is '$len'):
-------------------------|
+	elif test $len -lt 20; then
+		die 'Please make the first line at least 20 characters (yours is '$len'):
+-------------------|
 '"$line"'
-------------------------|'
-	elif test $len -gt 78 && ! msg_is_merge && ! msg_is_revert; then
+-------------------|'
+	elif test $len -gt 70 && ! msg_is_merge && ! msg_is_revert; then
 		die 'The first line may be at most 70 characters (to fit on github summary page):
 ---------------------------------------------------------------------|
 '"$line"'