Add warning statement.

Author: averagesecurityguy

modules/auxiliary/scanner/mysql/mysql_writable_dirs.rb

@@ -43,6 +43,7 @@ def mysql_query_no_handle(sql)
   end
 
   def run_host(ip)
+    print_warning("For every writable directory found, a file called test with the text test will be written to the directory."
     vprint_status("Login...")
 
     unless mysql_login_datastore