HADOOP-18661. Fix bin/hadoop usage script terminology. (#5473)

Followup to HADOOP-13209: s/slaves/r/workers in
the usage message you get when you type "bin/hadoop"

Contributed by Steve Loughran

hadoop-common-project/hadoop-common/src/main/bin/hadoop

@@ -26,9 +26,9 @@ MYNAME="${BASH_SOURCE-$0}"
 function hadoop_usage
 {
   hadoop_add_option "buildpaths" "attempt to add class files from build tree"
-  hadoop_add_option "hostnames list[,of,host,names]" "hosts to use in slave mode"
+  hadoop_add_option "hostnames list[,of,host,names]" "hosts to use in worker mode"
   hadoop_add_option "loglevel level" "set the log4j level for this command"
-  hadoop_add_option "hosts filename" "list of hosts to use in slave mode"
+  hadoop_add_option "hosts filename" "list of hosts to use in worker mode"
   hadoop_add_option "workers" "turn on worker mode"
 
   hadoop_add_subcommand "checknative" client "check native Hadoop and compression libraries availability"

hadoop-common-project/hadoop-common/src/main/bin/hadoop-daemons.sh

@@ -16,7 +16,7 @@
 # limitations under the License.
 
 
-# Run a Hadoop command on all slave hosts.
+# Run a Hadoop command on all worker hosts.
 
 function hadoop_usage
 {