Remove apachesolr_read_only check from Drupal_ Apache_Solr_Service::_sendRawPost()

Hi!

I've run into a problem while re-using Drupal_Apache_Solr_Service for my Apache Solr RDF project. Since the two modules use different Solr servers, it should be possible to set apachesolr to "read only", while still continuing to index RDF resources with apachesolr_rdf.
But since apachesolr_read_only gets checked not only in apachesolr_get_nodes_to_index(), but also in the service class' _sendRawPost() method, it can't be done without reimplementing that method in a new class and omitting these three lines.
Since this would be unnecessary code duplication, I wanted to ask if the check is really necessary there. Attached would be a patch removing it, in case it is not.

Also, I noticed that the documentation comment right above it refers to the wrong method, but this is of course another issue entirely. ;)