Allow immediately executing RPC with no input

Story: https://tree.taiga.io/project/jktjkt-netconf-cli/us/189
Change-Id: I876437b798e995c4484e97b409117a2bb207e864
diff --git a/src/interpreter.cpp b/src/interpreter.cpp
index acb3f0b..ac958dc 100644
--- a/src/interpreter.cpp
+++ b/src/interpreter.cpp
@@ -220,9 +220,12 @@
     m_parser.changeNode(prepare.m_path);
 }
 
-void Interpreter::operator()(const exec_&) const
+void Interpreter::operator()(const exec_& exec) const
 {
     m_parser.changeNode({Scope::Absolute, {}});
+    if (exec.m_path) {
+        m_datastore.initiate(pathToString(toCanonicalPath(*exec.m_path)));
+    }
     auto output = m_datastore.execute();
     std::cout << "RPC/action output:\n";
     printTree(output);