Fix the views specific hook_graphapi_default_settings

The default settings for a module should be just that and not a preparation of views quirks.

I ran into this again through option_definition() not having nested default values.

[edit: not the cause]
Changing

<?php
// Add settings provided by plugin engines.
- $options += module_invoke_all('graphapi_default_settings');
+ $engines = graphapi_views_formats();
+ foreach ($engines as $engine => $dummy) {
+ $from_engine = module_invoke( $engine, 'graphapi_default_settings');
+ $options[$engine] = $from_engine[$engine];
+ }

let the values be saved for ie graph_phyz physics settings.

XREF : Core: #222074: PHP bug/feature in array_merge_recursive() causes warning messages

There was a bug regarding boolean values. That's now fixed.

But it's not possible to remove the hook as modules know what their values are including translation. So we keep it this way.