Watchdog error when changing layout

Here's a patch that fixes this!

The fix itself is simple: the code in panels_edit_display_settings_form_submit() is using panels_plugin_get_function('layout', ...) whereas the name of the plugin type is actually 'layouts' (with an 's')

However, tracking down how this ever worked with an incorrect plugin type name, is a little more complicated!

Basically, the two forms (panels_edit_display_settings_form() and panels_change_layout()) both put the layout plugin in $form_state['layout'], except that the former is storing the full plugin definition as an array, and the latter is only storing the layout name as a string.

Looking at the code for panels_plugin_get_function():

function panels_plugin_get_function($plugin, $which, $function_name) {
  ctools_include('plugins');
  if (is_object($which) || is_array($which)) {
    return ctools_plugin_get_function($which, $function_name);
  }
  else {
    return ctools_plugin_load_function('panels', $plugin, $which, $function_name);
  }
}

If $which is an array, it completely ignores the passed in $plugin and just grabs the function name off the plugin definition, so it doesn't matter that the plugin type is wrong.

However, if a string is passed in, then it has to load the plugin definition at which point it uses the $plugin and that's where we're getting an error because the plugin type name was wrong.

Please let me know what you think!

lol. fixed.