Remove needless line "#define d d_ptr"

There was a time when qsslsocket.h declared its private slots as

Q_PRIVATE_SLOT(d, void _q_connectedSlot())

But now they are correctly declared as

Q_PRIVATE_SLOT(d_func(), void _q_connectedSlot())

so the "#define d d_ptr" hack isn't needed.
Specifically, the define would break moc-generated code that refers
to the member d of a structure (which a future moc revision does,
namely QByteArrayData::d).

Change-Id: Ic94fa4d523fb17e8088973cfc0d090d5cce97267
Reviewed-by: Jonas Gastal <jgastal@profusion.mobi>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/network/ssl/qsslsocket.cpp

@@ -2345,6 +2345,4 @@ QList<QByteArray> QSslSocketPrivate::unixRootCertDirectories()
 
 QT_END_NAMESPACE
 
-// For private slots
-#define d d_ptr
 #include "moc_qsslsocket.cpp"