catch connect problem in query call

mod_mysql.lua -  query does not return error on error, maybe change to;

function _M.query( connect_table, query )

  local response = coronium.newResponse()

  local answer = _connect( connect_table )

  //START

  if answer.error then

      response.error = answer.error

      response.errorCode = answer.errorCode

  end

  //END

  local db

  if not answer.error then

    db = answer.result