Eliminate the warning DeprecationWarning: the md5 module is deprecated; use hashlib instead
Eliminate the warning
DeprecationWarning: the md5 module is deprecated; use hashlib instead

Replace the md5 module with hashlib.
Add proper checks for Python < 2.5 which does not provide hashlib.

Signed-off-by: Abhishek Kulkarni <92d954836867f20d12bc943ae16aa9e7e694d1c8@osl.iu.edu>

wca/py9p.u