Handle non-integer chunk sizes in GridFS

The unofficial Lua driver can insert chunks into GridFS with float-type chunkSize. For example, the chunkSize might be "261120.0" instead of "261120" (BSON type 0x01 instead of type 0x10 or 0x12.) Perhaps PyMongo should handle this buggy input better.

Exception info:

File "/usr/lib64/python2.6/site-packages/pymongo-2.7-py2.6-linux-x86_64.egg/gridfs/grid_file.py", line 482, in read

    chunk_data = self.readchunk()

  File "/usr/lib64/python2.6/site-packages/pymongo-2.7-py2.6-linux-x86_64.egg/gridfs/grid_file.py", line 454, in readchunk

    chunk_data = chunk["data"][self.__position % self.chunk_size:]

TypeError: slice indices must be integers or None or have an __index__ method

Is chunk_size only int? Or int and float all are ok?

I found a way that modifies 'grid_file.py:454' from 'chunk_data = chunk["data"][self.__position % self.chunk_size:]' to 'chunk_data = chunk["data"][self.__position % int(self.chunk_size):]' to fix the bug.