[docs] simplify multi-master migration instructions

This patch updates the instructions for the multi-master migration
procedure by removing an extra conditional step based on the choice
whether DNS aliases were configured or not.

Change-Id: Ie9c530c194b40d658c7764dd553c5b16806dca90
Reviewed-on: http://gerrit.cloudera.org:8080/18500
Tested-by: Kudu Jenkins
Reviewed-by: Attila Bukor <abukor@apache.org>
1 file changed