Don't duplicate things the constructor has done

QCollator::detach() created a new QCollatorPrivate, then set some of
its fields to the values its constructor sets them to.  Don't waste
time doing that.

Change-Id: I048a1553753ae2cf03d3f61d45490f2723ee658b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qcollator.cpp

@@ -159,9 +159,7 @@ void QCollator::detach()
 {
     if (d->ref.load() != 1) {
         QCollatorPrivate *x = new QCollatorPrivate;
-        x->ref.store(1);
         x->locale = d->locale;
-        x->collator = 0;
         if (!d->ref.deref())
             delete d;
         d = x;