Switch to python builtin hash function generates too few partitions for tuple keys

[sumpfork]

Python 2.x: In 0.5.3 disco used md5 on a stringified version of the key mod the number of partitions to generate partition assignments by default. In 0.5.4 this switched to using the python hash() call. Calling this on tuples yields very few results when taken mod a low number like 100 - we're seeing in the range of 2-16 or so, yielding far few actual partitions than requested. Using strings works fine.

Seems like if keys need to be strings this should be enforced/documented, or a different hash function used?

[ghost]

#614