Fix undefined mssql_query on mssql client

Author: sjanusz-r7

lib/rex/post/mssql/ui/console.rb

@@ -58,7 +58,7 @@ def initialize(session, opts={})
 
           # @return [String]
           def database_name
-            session.client.mssql_query('SELECT DB_NAME();')[:rows][0][0]
+            session.client.query('SELECT DB_NAME();')[:rows][0][0]
           end
 
           # @param [Object] val