Update solr.yml to fix issue #108

remove slf4j-jcl.jar to avoid the error below on SOLR startup.

IllegalStateException: Detected both jcl-over-slf4j.jar AND slf4j-jcl.jar on the class path, preempting StackOverflowError. See also http://www.slf4j.org/codes.html#jclDelegationLoop for more details.