Validations fail if we add unused hypervisors

[Carlos Camacho Gonzalez]

Describe the bug
Validations fail if we add unused hypervisors

When we have 3 hosts available in the inventory (nyctea, tyto, strix) but we allocate the guests to only 2 (nyctea, tyto) the validations will fail as it is not defined how much is used in those 'unused' hypervisors.

To Reproduce
100% of the times

1. Periodic job https://storage.googleapis.com/kubeinit-ci/jobs/okd-libvirt-3-0-3-v-c-periodic-pid-weekly-u/index.html

Expected behavior
The validation should pass

Additional context

Task result details
Play: Main deployment play for creating a cluster
Task: ../../roles/kubeinit_validations : Make sure there is enough free space
Action: ansible.builtin.assert
Path: /kubeinit/kubeinit/roles/kubeinit_validations/tasks/10_libvirt_free_space.yml:104
Host: localhost
Status: failed
Started: 09 Aug 2021 10:42:08 +0000
Ended: 09 Aug 2021 10:42:08 +0000
Duration: 00:00:00.04

msg | The conditional check 'kubeinit_validations_hypervisors_free_disk_space[item.key]\|int > item.value\|float * 1.1' failed. The error was: error while evaluating conditional (kubeinit_validations_hypervisors_free_disk_space[item.key]\|int > item.value\|float * 1.1): 'dict object' has no attribute 'hypervisor-03'