podman: default the hostname to the name of the platform

This was the case in the past (and is still the case for the Docker
driver), but was accidentally changed in an unrelated refactoring.

Fixes: e9d5649

src/molecule_plugins/podman/playbooks/create.yml

@@ -146,7 +146,7 @@
         etc_hosts: "{{ item.etc_hosts | default(omit) }}"
         executable: "{{ podman_exec }}"
         expose: "{{ item.exposed_ports | default(omit) }}"
-        hostname: "{{ item.hostname | default(omit) }}"
+        hostname: "{{ item.hostname | default(item.name) }}"
         image: "{{ item.pre_build_image | default(false) | ternary('', 'molecule_local/') }}{{ item.image }}"
         ip: "{{ item.ip | default(omit) }}"
         label: