Remove no-op calls to swig_incref().

Python and Perl were calling this from the Director constructor, but
swig_disown_flag is always false at that point, so the call doesn't
do anything.

Lib/perl5/director.swg

@@ -233,7 +233,6 @@ namespace Swig {
       char *str = SvPV(pkg, len);
       swig_class = std::string(str, len);
       swig_self = newRV_inc((SV *)newHV());
-      swig_incref();
     }
 
     /* discard our reference at destruction */

Lib/python/director.swg

@@ -330,7 +330,6 @@ namespace Swig {
   public:
     /* wrap a python object, optionally taking ownership */
     Director(PyObject *self) : swig_self(self), swig_disown_flag(false) {
-      swig_incref();
     }
 
     /* discard our reference at destruction */