Fixed problem where solr install path becomes /opt/solr-4.6.1/solr-4.6.1/

The cookbook tries to untar the contents of the Apache Solr tgz files into a directory that it creates like: /opt/solr-4.6.1/ 

However, the tgz root contains this folder as well meaning that everything is installed into:
/opt/solr-4.6.1/solr-4.6.1/

Using tar with the --strip 1 option avoids this and means that the scripts can then find the solr binaries etc.