Fix version fingerprinting

Author: rastating

modules/exploits/spiffy_calendar_reflected_xss_shell_upload.rb

@@ -29,7 +29,8 @@ def initialize
   end
 
   def check
-    check_plugin_version_from_changelog('spiffy-calendar', 'readme.txt', '3.2.1')
+    readme = normalize_uri(wordpress_url_plugins, 'spiffy-calendar', 'readme.txt')
+    check_version_from_custom_file(readme, /=\sVersion\s((\d+\.?)+).+?=/, '3.3')
   end
 
   def vulnerable_url