tests: Validate that JSON deflattening fixed nested json pseudo-protocol strings

Sheepdog and possibly others use nested objects for network server and
thus could be specified in a way that libvirt would not parse.

Validates that https://bugzilla.redhat.com/show_bug.cgi?id=1464821
is fixed properly.

tests/virjsondata/deflatten-qemu-sheepdog-in.json

+{
+    "driver": "raw",
+    "file": {
+        "server.host": "10.10.10.10",
+        "server.port": "7000",
+        "tag": "",
+        "driver": "sheepdog",
+        "server.type": "inet",
+        "vdi": "Alice"
+    }
+}

tests/virjsondata/deflatten-qemu-sheepdog-out.json

+{
+  "driver": "raw",
+  "file": {
+    "server": {
+      "host": "10.10.10.10",
+      "port": "7000",
+      "type": "inet"
+    },
+    "tag": "",
+    "driver": "sheepdog",
+    "vdi": "Alice"
+  }
+}

tests/virjsontest.c

@@ -519,6 +519,7 @@ mymain(void)
     DO_TEST_DEFLATTEN("double-key", false);
     DO_TEST_DEFLATTEN("concat", true);
     DO_TEST_DEFLATTEN("concat-double-key", false);
+    DO_TEST_DEFLATTEN("qemu-sheepdog", true);
 
     return (ret == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
 }

tests/virstoragetest.c

@@ -1575,6 +1575,16 @@ mymain(void)
                        "<source protocol='sheepdog' name='test'>\n"
                        "  <host name='example.com' port='321'/>\n"
                        "</source>\n");
+    TEST_BACKING_PARSE("json:{\"driver\": \"raw\","
+                             "\"file\": {\"server.host\": \"10.10.10.10\","
+                                        "\"server.port\": \"7000\","
+                                        "\"tag\": \"\","
+                                        "\"driver\": \"sheepdog\","
+                                        "\"server.type\": \"inet\","
+                                        "\"vdi\": \"Alice\"}}",
+                       "<source protocol='sheepdog' name='Alice'>\n"
+                       "  <host name='10.10.10.10' port='7000'/>\n"
+                       "</source>\n");
 #endif /* WITH_YAJL */
 
  cleanup: