BUG: fix max recursion error in test_reindex_items

It looks like sorting by dtype itself does not work.
To see that, try this snippet:

>>> from numpy import dtype
>>> sorted([dtype('bool'), dtype('float64'), dtype('complex64'),
...         dtype('float64'), dtype('object')])
[dtype('bool'),
 dtype('float64'),
 dtype('complex64'),
 dtype('float64'),
 dtype('object')]

Author: tkf

pandas/core/internals.py

@@ -1135,7 +1135,7 @@ def _consolidate(blocks, items):
     """
     Merge blocks having same dtype
     """
-    get_dtype = lambda x: x.dtype
+    get_dtype = lambda x: x.dtype.name
 
     # sort by dtype
     grouper = itertools.groupby(sorted(blocks, key=get_dtype),