Don't add E_ERROR back to error reporting level if level is changed outside of Catcher #6

If error_reporting is set to something outside of Catcher after Catcher is instantiated then that should be assumed to be what is wanted as the error reporting level.

Example:

$catcher = new Catcher();
error_reporting(\E_ALL & ~\E_ERROR);
$catcher->unregister();
echo error_reporting();

Output:

32767 // E_ALL

The actual output should be:

32766 // E_ALL & ~E_ERROR

This is because the reporting level was explicitly set again after Catcher instantiated.

Fixed by 3ad4620d0c.