Description
As noted in email a while back...
but there is currently no assertion that every core have a name, or that the
names be unique before the SolrCore is constructed ... it's not until the core is registered that an error will be
generated if the core name is null, or that the previous core with an identicle name will be close()ed.
I think we should fail fast if solr.xml specifies the same name more then once