Description of problem:
-----------------------
The current way the blacklisting gluster devices works is such a way it configures vdsm with force option, to generate /etc/multipath.conf, so that that multipathd service could be started. This is true for fresh installation , as that doesn't have the /etc/multipath.conf file.

But considering for day2 operation, when creating a new volume or expanding cluster, it will once again configure vdsm with force option, which will override the existing vdsm configuration.

So the solution is to configure vdsm with force, only and only if /etc/multipath.conf file is *not* available

Version-Release number of selected component (if applicable):
-------------------------------------------------------------
gluster-ansible-infra-1.0.4-7

How reproducible:
-----------------
Always

Steps to Reproduce:
--------------------
1. Complete RHHI-V deployment by blacklisting the gluster devices
2. From Day2, start with volume creation or cluster expansion operation

Actual results:
-----------------
vdsm is configured once again losing the old value

Expected results:
-----------------
As /etc/multipath.conf file already exists, configuring vdsm with force option is not required

Additional info:
----------------
Code logic should be:

if (the file /etc/multipath.conf **not** present):
    vdsm-tool configure --force
    Blacklist_devices()
else:
    Blacklist_devices()