SolrCloud can select a core not in active state for querying

A query can be served by a core which is not in active state if the request hits the node which hosts these non active cores.

We explicitly check for only active cores to search against in CloudSolrClient#sendRequest Line 1043 on trunk.

But we don't check this if someone uses the REST APIs

HttpSolrCall#getCoreByCollection should only pick cores which are active on line 794 on trunk.

We however check it on line 882/883 in HttpSolrCall, when we try to find cores on other nodes when it's not present locally.

So let's fix HttpSolrCall#getCoreByCollection to make the active check as well.