Port twisted.python.randbytes to Python 3

[exarkun]

This is needed by twisted.names.dns.

[exarkun]

(In [35956]) Branching to 'randbytes-py3-6061'

[exarkun]

Okay, worse than I thought, and the module is somewhat useless now that its alternative-selection features have been deleted. Oh well, I did it anyway, and I wish it had been easier and more useful. Build started:  http://buildbot.twistedmatrix.com/boxes-supported?branch=/branches/randbytes-py3-6061

[itamar]

I was actually going to suggest (in a new ticket) the use of randrange elsewhere in twisted.names.dns be switched to something secure based on inputs from os.urandom. Probably randbytes would be a reasonable place to add that sort of thing, so might be worth keeping around.

[exarkun]

What do you mean "switched to something secure"? That's the point of twisted.python.randbytes.secureRandom, which is what twisted.names.dns currently uses.

[itamar]

DNSMixin.__init__ uses randrange; not sure if that id has any meaning or use though.

[exarkun]

Ah. Good catch! That id looks unused to me. Perhaps I'll delete it.

[itamar]

Looks good, please merge.

(We should keep our eye out and see if we want to make a twisted.python.compat.bytechr if this comes up again.)

[exarkun]

(In [35963]) Merge randbytes-py3-6061

Author: exarkun Reviewer: itamarst Fixes: #6061

Port twisted.python.randbytes to Python 3.