update module description

Author: itsecurityco

modules/exploits/multi/http/x7chat2_php_exec.rb

@@ -16,7 +16,7 @@ def initialize(info = {})
 			'Name'           => 'The X7 Group X7 Chat 2.0.5 lib/message.php preg_replace() PHP Code Execution',
 			'Description'    => %q{
 				Library lib/message.php for X7 Chat 2.0.5 uses preg_replace() function with the /e modifier.
-        		This allow execute PHP code in the remote machine.
+        		This allows execute PHP code in the remote machine.
 			},
 			'License'        => MSF_LICENSE,
 			'Author'         =>