Fixed incorrect usage of memoryview. It's not getting faster though

[ skip ci ]

Author: Byron

smmap/util.py

@@ -23,7 +23,7 @@
 except NameError:
     # Python 3 has no `buffer`; only `memoryview`
     def buffer(obj, offset, size):
-        # return memoryview(obj[offset:offset+size])
+        # return memoryview(obj)[offset:offset+size]
         # doing it directly is much faster !
         return obj[offset:offset+size]