If gst_index_factory_new() finds a factory via gst_index_factory_find(), it
simply  returns it without increasing its refcount.  Usually, constructors
return a new object, so the receiver can always assume ownership without
manually increasing the refcount himself.  In this case, the receiver can't be
sure if he really owns the factory, which leads to either segfaults or leaks.

This is especially visible in language bindings which need to be very careful
about refcounts to avoid having dangling pointers all over the place.