added password parameter for automated install

As requested for the use with Vagrant I added an ption to Keystone.sh
so it can be called with the mysql root password as a parameter.
The interactive option is still available if the script is called
without a parameter

Cleaned up some comments and prompts

Change-Id: I754a9baba2d7b30b5105e45130f57142cb4614be

doc/training-guide/training-labs/Scripts/Keystone/Keystone.sh

@@ -73,13 +73,17 @@ keystone_conf() {
     # Load the Auth Creds
     source Scripts/Credentials.sh
 
-    # Check The Keystone Useres
+    # List keystone users
     keystone user-list
 }
 
-# Create required MySQL Databases and Populate It.
-echo "Enter MySQL root pass"
-read MySQL_RPaSS
+if [ "$#" -ne 1 ]; then
+    # Create and populate required MySQL databases
+    echo "Enter MySQL root password:"
+    read MySQL_RPaSS
+else
+    MySQL_RPaSS=$1
+fi
 
 echo "Running pre_keystone"
 pre_keystone