Fix rapid7#6677, typo fix for atutor_sqli

Author: wvu

modules/exploits/multi/http/atutor_sqli.rb

@@ -16,7 +16,7 @@ def initialize(info={})
       'Name'           => 'ATutor 2.2.1 SQL Injection / Remote Code Execution',
       'Description'    => %q{
          This module exploits a SQL Injection vulnerability and an authentication weakness
-         vulnerability in ATutor. This essentially means an attacker can bypass authenication
+         vulnerability in ATutor. This essentially means an attacker can bypass authentication
          and reach the administrator's interface where they can upload malicious code.
       },
       'License'        => MSF_LICENSE,