[Test] IndexLifecycleActionTests - set minimum master node earlier to make sure it's in effect when needed.
[Test] FullRollingRestartTests - correctly setting minimum_master_nodes

Also added a ElasticsearchIntegrationTest.setMinimumMasterNodes() helper function.
[Tests] QuorumLocalGatewayTests - Set mini_master_nodes earlier to make sure it has effect.  ClusterServiceTests - remove a thread.sleep in favor of awaitBusy
[DOCS] Reword clear-scroll sentence
[DOCS] Fixing contributing.md indentation

Add a whitespace to make these separate paragraphs inside of a list.