Prefer emplace_back

Found by clang-tidy.

Change-Id: I33149bf98087f1e35ccb5a888831fc2db2ece7c0
diff --git a/tests/prepare.cpp b/tests/prepare.cpp
index 139ef4b..d56a488 100644
--- a/tests/prepare.cpp
+++ b/tests/prepare.cpp
@@ -28,14 +28,14 @@
     SECTION("rpc")
     {
         input = "prepare example:fire";
-        expected.m_path.m_nodes.push_back({module_{"example"}, rpcNode_{"fire"}});
+        expected.m_path.m_nodes.emplace_back(module_{"example"}, rpcNode_{"fire"});
     }
 
     SECTION("action")
     {
         input = "prepare example:port[name='eth0']/shutdown";
-        expected.m_path.m_nodes.push_back({module_{"example"}, listElement_{"port", {{"name", std::string{"eth0"}}}}});
-        expected.m_path.m_nodes.push_back({actionNode_{"shutdown"}});
+        expected.m_path.m_nodes.emplace_back(module_{"example"}, listElement_{"port", {{"name", std::string{"eth0"}}}});
+        expected.m_path.m_nodes.emplace_back(actionNode_{"shutdown"});
     }
 
     command_ command = parser.parseCommand(input, errorStream);