Disable copy and move operations in TlsKey

TlsKeyOpenSSL has a custom constructor but no other special member
functions. Instead of disabling them in TlsKeyOpenSSL, disable them in
the base class.

Amends 1a0da3ae69964142b3a31d87ecc88a925006a4de.

Pick-to: 6.7 6.5 6.2
Task-number: QTBUG-125026
Change-Id: I54f3ac01f89a21b8665c4d82a8f38dedab9bb5c3
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
(cherry picked from commit 05d4740623477eda83c1ce544aeadffba3014806)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/network/ssl/qtlsbackend_p.h

@@ -59,6 +59,9 @@ namespace QTlsPrivate {
 
 class Q_NETWORK_EXPORT TlsKey {
 public:
+    TlsKey() = default;
+    Q_DISABLE_COPY_MOVE(TlsKey)
+
     virtual ~TlsKey();
 
     using KeyType = QSsl::KeyType;