Fix 'get_pickle_metadata' for protocol > 1 on Python2.

src/ZODB/utils.py

@@ -217,8 +217,9 @@ def get_pickle_metadata(data):
     # ZODB's data records contain two pickles.  The first is the class
     # of the object, the second is the object.  We're only trying to
     # pick apart the first here, to extract the module and class names.
-    if data[0] == 0x80:       # protocol marker, protocol > 1
-        protocol = data[1]
+    if data[0] in (0x80,    # Py3k indexes bytes -> int
+                   b'\x80'  # Python2 indexes bytes -> bytes
+                  ): # protocol marker, protocol > 1
         data = data[2:]
     if data.startswith(b'(c'):   # pickle MARK GLOBAL opcode sequence
         global_prefix = 2