Add info to get rid of 'multiple bindings' warning from SLF4J.
Add info to get rid of 'multiple bindings' warning from SLF4J.

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1762193 13f79535-47bb-0310-9956-ffa450edef68

Former-commit-id: 353c496eed5ad5a988e67d372b2c73175a03f5f1
ham1/jmeter,apache/jmeter,etnetera/jmeter,etnetera/jmeter,benbenw/jmeter,ham1/jmeter,apache/jmeter,ham1/jmeter,ham1/jmeter,apache/jmeter,etnetera/jmeter,apache/jmeter,etnetera/jmeter,apache/jmeter,benbenw/jmeter,benbenw/jmeter,etnetera/jmeter,ham1/jmeter,benbenw/jmeter