Loaded real destructor functions before garbage time

This is an alternative patch to the unsuccessful b43b27bcd.

django/contrib/gis/geos/prototypes/io.py

@@ -125,6 +125,11 @@ class IOBase(GEOSBase):
     def __init__(self):
         # Getting the pointer with the constructor.
         self.ptr = self._constructor()
+        # Loading the real destructor function at this point as doing it in
+        # __del__ is too late (import error).
+        self._destructor.func = self._destructor.get_func(
+            *self._destructor.args, **self._destructor.kwargs
+        )
 
     def __del__(self):
         # Cleaning up with the appropriate destructor.