[deployment_handler] Fix problem when trying to run ovs-vsctl on Fuel

[deployment_handler] Fix problem when trying to run ovs-vsctl on Fuel

When creating a Node object, it fetches the ovs version
in the init method. This prevents doing this if the
node is the installer. Anyways, the information
about the installer node is not showed.

Error:
opnfv.deployment.manager - ERROR - error bash: ovs-vsctl: command not found

Example of this output:
https://build.opnfv.org/ci/view/functest/job/functest-fuel-baremetal-daily-master/1161/consoleFull

Change-Id: I7b5d41af438e18dffa3b1eab2c9279164a4d4fc2
Signed-off-by: jose.lausuch <jose.lausuch@ericsson.com>