ipadnsrecord: Fix for ansible-test fake execution test

All imports that are only available after installing IPA need to be in a
try exception clause to be able to pass the fake execution test.

If the imports can not be done, all used and needed attributes are
defined with the value None, MODULE_IMPORT_ERROR is set to the import
error and fail_json is called.

plugins/modules/ipadnsrecord.py

@@ -866,8 +866,13 @@ RETURN = """
 from ansible.module_utils._text import to_text
 from ansible.module_utils.ansible_freeipa_module import \
     IPAAnsibleModule, is_ipv4_addr, is_ipv6_addr, ipalib_errors
+try:
     import dns.reversename
     import dns.resolver
+except ImportError as _err:
+    MODULE_IMPORT_ERROR = str(_err)
+else:
+    MODULE_IMPORT_ERROR = None
 
 from ansible.module_utils import six
 
@@ -1131,6 +1136,9 @@ def configure_module():
 
     ansible_module._ansible_debug = True
 
+    if MODULE_IMPORT_ERROR is not None:
+        ansible_module.fail_json(msg=MODULE_IMPORT_ERROR)
+
     return ansible_module