Don't specify base 0 to string.atoi when unpickling integers in text

mode.  The pickler always uses base 10 so the default base should be
fine.  (The base gets us in trouble when there's no strop module, as
the atoi() in string.py only supports base 10.  This is for JPython.)

Lib/pickle.py

@@ -519,7 +519,7 @@ class Unpickler:
     dispatch[NONE] = load_none
 
     def load_int(self):
-        self.append(string.atoi(self.readline()[:-1], 0))
+        self.append(string.atoi(self.readline()[:-1]))
     dispatch[INT] = load_int
 
     def load_binint(self):