Fix 500 when saving /site/edit without email
When saving /site/edit with no no_reply_email set, a 500 error page
would be returned due to an empty value being passed as value to
the datastore (which is not allowed for email fields).
"""
The md5 and sha modules are deprecated since Python 2.5, replaced by the
hashlib module containing both hash algorithms. Here, we provide a common
interface to the md5 and sha constructors, preferring the hashlib module when
available.
"""
try:
import hashlib
md5_constructor = hashlib.md5
sha_constructor = hashlib.sha1
except ImportError:
import md5
md5_constructor = md5.new
import sha
sha_constructor = sha.new