HNAS driver: Fix SSH and cluster_admin_ip0 bug

HNAS driver: Fix SSH and cluster_admin_ip0 bug

HNAS driver has 2 configuration options:
- SSC (ssh_enabled: False ): requires a local utility package
installed to run the commands
- SSH (ssh_enabled: True): Runs the commands using the utility
package installed on HNAS

Currently, the HNAS driver is considering the "ssh_enabled" and the
"cluster_admin_ip0" tags to decide if the command to get the utility
package version should be ran locally or not. This is not correct
because the "cluster_admin_ip0" tag is not mandatory even if the SSH
mode is enabled.
So, if we have a situation that SSH is enabled and the
"cluster_admin_ip0" does not exist in the configuration, the driver
tries to run the command to get the utility package version locally
and its initialization breaks.
This patch makes the driver consider only the "ssh_enabled" tag
value to decide if the command to get the utility package version
is necessary.

Change-Id: I29fb5d7199e10eafee329dbd4ccef524245fbc28
Closes-Bug: 1543208