MB-100: duplicate code for centos, rh uninstall part

Change-Id: Ifa29ceca18df8df8107780c23ae4cf1abefa6c91
Reviewed-on: http://review.couchbase.org/24766
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: buildbot <build@couchbase.com>