Do not write the rows in calendar cat. report if all columns are zero

calendar/inc/class.calendar_category_report.inc.php

@@ -397,6 +397,14 @@ class calendar_category_report extends calendar_ui{
 
 				foreach ($raw_csv as &$row)
 				{
+					$check_row = 0;
+					foreach ($row as $val)
+					{
+						$check_row += $val;
+					}
+					//check if all values of the row is zero then escape the row
+					if (!$check_row) continue;
+					
 					// printout each row into file
 					fputcsv($fp, array_values($row));
 				}