Unlimited Solr query are not properly handled by the SolrEventStore

Solr doesn't allow to perform query returning an unlimited number of rows.
If the rows parameter is not set, the default is to return 10 results.
However we defined in the Solr API that if the limit is -1, the returned number of results should be unlimited. And this contract is not respected in SolrEventStore since toSolrQuery is just ommitting the rows parameter in that case, leading to a limit of 10.