'ansible_memory_mb' is undefined

[gk-fschubert]

The PR https://github.com/geerlingguy/ansible-role-swap/pull/36/commits indroduced a issue for our servers:

fatal: [xxx.xxx.xxx.xxx]: FAILED! => {"msg": "The conditional check 'ansible_memory_mb['swap']['total'] > 0' failed. The error was: error while evaluating conditional (ansible_memory_mb['swap']['total'] > 0): 'ansible_memory_mb' is undefined. 'ansible_memory_mb' is undefined\n\nThe error appears to be in '/ansible-resources/roles/swap/tasks/disable.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- name: Disable swap (if configured).\n ^ here\n"}