NetconfAccess: enable passing libnetconf2 (C++) session directly

Instead of implementing all possible constructors twice, rely on the
underlying library (or rather its C++ bindings) to do the right thing,
and use that as a connection handle.

Change-Id: I954edc9bfbd1c909479db6b92b929aab93762810
diff --git a/src/netconf_access.cpp b/src/netconf_access.cpp
index 78d80b1..4f4a923 100644
--- a/src/netconf_access.cpp
+++ b/src/netconf_access.cpp
@@ -98,6 +98,13 @@
     datastoreInit();
 }
 
+NetconfAccess::NetconfAccess(std::unique_ptr<libnetconf::client::Session>&& session)
+    : m_session(std::move(session))
+    , m_schema(new YangSchema())
+{
+    datastoreInit();
+}
+
 NetconfAccess::NetconfAccess(const std::string& socketPath)
     : m_schema(new YangSchema())
 {