Fix the import of RVM GPG keys

This was consistently failing on our CI with Ubuntu 22.04 and Ubuntu
24.04 since a few weeks ago, for unknown reasons (it used to work fine
most of the time).

galaxy/rvm.ruby/tasks/rvm.yml

@@ -27,7 +27,7 @@
   check_mode: False
   with_items: '{{ rvm1_gpg_key_servers }}'
   register: gpg_import
-  when: not ansible_check_mode and rvm1_gpg_keys != '' and (gpg_import is not defined or gpg_import.rc != 0)
+  when: not ansible_check_mode and rvm1_gpg_keys != '' and (gpg_import is not defined or (gpg_import.rc is defined and gpg_import.rc != 0))
   ignore_errors: True
 
 - name: Was GPG import from keyservers succesfull?