libcnary: Fix possible NULL pointer dereference in node_iterator_create()
libcnary: Fix possible NULL pointer dereference in node_iterator_create()

When NULL is passed to node_iterator_create() the code tries to access
the begin element of the node list and causes a NULL pointer dereference.
The value of list is checked a few lines down and iterator->value is then
properly assigned in node_iterator_bind().

Tatsh/libplist,Tatsh/libplist,libimobiledevice-win32/libplist,Tatsh/libplist,libimobiledevice/libplist,libimobiledevice-win32/libplist,libimobiledevice/libplist,libimobiledevice-win32/libplist,libimobiledevice/libplist,Tatsh/libplist,libimobiledevice-win32/libplist