[Minor]fix the wrong description

Found it by accident. I'm not gonna file jira for this as it is a very tiny fix.

Author: WangTaoTheTonic <wangtao111@huawei.com>

Closes #4936 from WangTaoTheTonic/wrongdesc and squashes the following commits:

fb8a8ec [WangTaoTheTonic] fix the wrong description
aca5596 [WangTaoTheTonic] fix the wrong description

sbin/stop-all.sh

@@ -17,8 +17,8 @@
 # limitations under the License.
 #
 
-# Start all spark daemons.
-# Run this on the master nde
+# Stop all spark daemons.
+# Run this on the master node.
 
 
 sbin="`dirname "$0"`"

sbin/stop-master.sh

@@ -17,7 +17,7 @@
 # limitations under the License.
 #
 
-# Starts the master on the machine this script is executed on.
+# Stops the master on the machine this script is executed on.
 
 sbin=`dirname "$0"`
 sbin=`cd "$sbin"; pwd`