1.4 upgrade document incorrect commands need to be fixed

These issues were found in the 1.4 upgrade document for single server. They need to be corrected and make sure all upgrade documents are correct.

https://mariadb.com/docs/deploy/upgrade-single-columnstore/

1. The upgrade documentation says to do this:

mcsadmin stopSystem

But it should say this:

mcsadmin shutdownSystem

2. The CentOS upgrade documentation says to do this:

sudo yum remove "MariaDB-columnstore-*"

But it should say this:

sudo yum remove "mariadb-columnstore-*"