No options when facet's field name contains colon chars

Hi there,

I found this problem when dealing with some custom solr fields. Their names where something like core_lodging_product:baths, because a related entity was used, and then the baths field in that entity, resulting in a compound name.

The thing is the select widget build process gets confused when colon ( : ) chars are in the way, because internally it uses a explode(':', ... ) call, to get the name.

The fix is in the patch attached. It gets the facet name from a different source in the same object. I tested it but couldn't find a scenario where it does not work. I assume the $this->build['#settings']->name was used instead of the more direct option $this->facet['field alias'] for a reason, but I'm not sure why.

Thanks
@dalguete