Solr indexing callback assumes field is added to a node

geofield_apachesolr_index() makes the assumption that it is always being called in the context of a field on a node being indexed. This fails for non-node entites.

In apachesolr, #1838802: Add $entity_type parameter to field indexing callbacks will add an $entity_type parameter for field indexing callbacks. The attached patches update the field indexing callbacks in Geofield 7.x-2.x and 7.x-1.x to be entity-agnostic.

They depend on the #1838802: Add $entity_type parameter to field indexing callbacks getting accepted.