Destroy Node's handle before its Link

Fixes #659.

Nodes must first delete the handle to the underlying hdf5
resource before deleting their link.
Otherwise (i.e., link is deleted first), hdf5 attempts to
close the file (if this was the last node referencing the
file), which might fail (e.g., when using mpi-io, or close
degree `Semi`) because the handle to the node would still
be around.

src/h5cpp/node/node.cpp

@@ -32,20 +32,20 @@ namespace node {
 
 Node::Node():
     attributes(*this),
-    handle_(),
-    link_()
+    link_(),
+    handle_()
 {}
 
 Node::Node(ObjectHandle &&handle,const Link &link):
     attributes(*this),
-    handle_(std::move(handle)),
-    link_(link)
+    link_(link),
+    handle_(std::move(handle))
 {}
 
 Node::Node(const Node &node):
     attributes(*this),
-    handle_(node.handle_),
-    link_(node.link_)
+    link_(node.link_),
+    handle_(node.handle_)
 {}
 
 Node &Node::operator=(const Node &node)

src/h5cpp/node/node.hpp

@@ -130,8 +130,8 @@ class DLL_EXPORT Node
     attribute::AttributeManager attributes;
 
   private:
-    ObjectHandle handle_; //!< access handle to the object
     Link link_;           //!< stores the link to the object
+    ObjectHandle handle_; //!< access handle to the object
 };
 
 DLL_EXPORT bool operator==(const Node &lhs, const Node &rhs);