test_dnszone.yml: Add failed_when and idempotency test

For test zones test1, test2 and test3 there is no verification if the
task is setting changed flag and also is not failing. Also the repeated
tests for idempotency are missing.

tests/dnszone/test_dnszone.yml

@@ -151,16 +151,43 @@
     ipadnszone:
       ipaadmin_password: SomeADMINpassword
       name: test1.testzone.local
+    register: result
+    failed_when: not result.changed or result.failed
+
+  - name: Create zones test1, again
+    ipadnszone:
+      ipaadmin_password: SomeADMINpassword
+      name: test1.testzone.local
+    register: result
+    failed_when: result.changed or result.failed
 
   - name: Create zones test2
     ipadnszone:
       ipaadmin_password: SomeADMINpassword
       name: test2.testzone.local
+    register: result
+    failed_when: not result.changed or result.failed
+
+  - name: Create zones test2, again
+    ipadnszone:
+      ipaadmin_password: SomeADMINpassword
+      name: test2.testzone.local
+    register: result
+    failed_when: result.changed or result.failed
 
   - name: Create zones test3
     ipadnszone:
       ipaadmin_password: SomeADMINpassword
       name: test3.testzone.local
+    register: result
+    failed_when: not result.changed or result.failed
+
+  - name: Create zones test3, again
+    ipadnszone:
+      ipaadmin_password: SomeADMINpassword
+      name: test3.testzone.local
+    register: result
+    failed_when: result.changed or result.failed
 
   - name: Ensure multiple zones are absent
     ipadnszone: