De-inline ~QHttpNetworkHeader()

... and adapt the whole hierarchy to idiomatic dtors (add override,
remove virtual).

Fixes -Wweak-vtable and all the problems that violating it brings.

Pick-to: 6.8
Task-number: QTBUG-45582
Change-Id: I180c774a135b1fbf1a7e942c91af25710a4bf5fd
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>

src/network/access/qhttpnetworkheader.cpp

@@ -7,6 +7,9 @@
 
 QT_BEGIN_NAMESPACE
 
+QHttpNetworkHeader::~QHttpNetworkHeader()
+    = default;
+
 QHttpNetworkHeaderPrivate::QHttpNetworkHeaderPrivate(const QUrl &newUrl)
     :url(newUrl)
 {

src/network/access/qhttpnetworkheader_p.h

@@ -31,7 +31,7 @@ QT_BEGIN_NAMESPACE
 class Q_AUTOTEST_EXPORT QHttpNetworkHeader
 {
 public:
-    virtual ~QHttpNetworkHeader() {}
+    virtual ~QHttpNetworkHeader();
     virtual QUrl url() const = 0;
     virtual void setUrl(const QUrl &url) = 0;
 

src/network/access/qhttpnetworkreply_p.h

@@ -60,7 +60,7 @@ class Q_NETWORK_EXPORT QHttpNetworkReply : public QObject, public QHttpNetworkHe
 public:
 
     explicit QHttpNetworkReply(const QUrl &url = QUrl(), QObject *parent = nullptr);
-    virtual ~QHttpNetworkReply();
+    ~QHttpNetworkReply() override;
 
     QUrl url() const override;
     void setUrl(const QUrl &url) override;

src/network/access/qhttpnetworkrequest_p.h

@@ -52,7 +52,7 @@ public:
 
     explicit QHttpNetworkRequest(const QUrl &url = QUrl(), Operation operation = Get, Priority priority = NormalPriority);
     QHttpNetworkRequest(const QHttpNetworkRequest &other);
-    virtual ~QHttpNetworkRequest();
+    ~QHttpNetworkRequest() override;
     QHttpNetworkRequest &operator=(const QHttpNetworkRequest &other);
     bool operator==(const QHttpNetworkRequest &other) const;