SOLR-7602: Check if SolrCore object is already closed before trying to close it in case of an exception during Core creation.(merge from branch_5x)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_5_2@1682346 13f79535-47bb-0310-9956-ffa450edef68
1 file changed