bugs.webkit.org internal server error when limiting search by 1 month

https://bugs.webkit.org/show_bug.cgi?id=257546
rdar://110075621

Reviewed by Alexey Proskuryakov.

Fixed SqlifyDate function in Bugzilla/Search.pm such that it multiplies month by 31 days and returns valid date.
Previously it would change only the month and keep the day of the month the same, causing invalid dates to be
returned depending on certain dates and how far to go back to.

* Websites/bugs.webkit.org/Bugzilla/Search.pm:
(SqlifyDate):

Canonical link: https://commits.webkit.org/264820@main

Websites/bugs.webkit.org/Bugzilla/Search.pm

@@ -2217,7 +2217,20 @@ sub SqlifyDate {
         my ($sec, $min, $hour, $mday, $month, $year, $wday)  = localtime($date);
         if ($sign && $sign eq '+') { $amount = -$amount; }
         $startof = 1 if $amount == 0;
-        if ($unit eq 'w') {                  # convert weeks to days
+# WEBKIT_CHANGES: Fixed invalid date returns on some occasions.
+        if ($unit eq 'm') {
+            $month -= $amount;
+            $year += floor($month/12);
+            $month %= 12;
+            if ($startof) {
+                return sprintf("%4d-%02d-01 00:00:00", $year+1900, $month+1);
+            }
+            else {
+                $amount = 31*$amount;
+                $unit = 'd';
+            }
+        }
+        elsif ($unit eq 'w') {                  # convert weeks to days
             $amount = 7*$amount;
             $amount += $wday if $startof;
             $unit = 'd';
@@ -2239,18 +2252,6 @@ sub SqlifyDate {
                                $year+1900-$amount, $month+1, $mday, $hour, $min, $sec);
             }
         }
-        elsif ($unit eq 'm') {
-            $month -= $amount;
-            $year += floor($month/12);
-            $month %= 12;
-            if ($startof) {
-                return sprintf("%4d-%02d-01 00:00:00", $year+1900, $month+1);
-            }
-            else {
-                return sprintf("%4d-%02d-%02d %02d:%02d:%02d", 
-                               $year+1900, $month+1, $mday, $hour, $min, $sec);
-            }
-        }
         elsif ($unit eq 'h') {
             # Special case for 'beginning of an hour'
             if ($startof) {