[binding][python] fixup python 3 compatibility

In Python 3.x dict.keys() return a dict_keys object not a list.

bindings/python/capstone/__init__.py

@@ -875,8 +875,7 @@ def debug():
 
     all_archs = ""
     keys = archs.keys()
-    keys.sort()
-    for k in keys:
+    for k in sorted(keys):
         if cs_support(archs[k]):
             all_archs += "-%s" % k