SHA{1,512}: Rename structs and functions

	By ensuring that the SHA1 and SHA512 code in Cherokee does
	not stomp on symbols provided by libssl, we prevent a problem
	where the relative sizes of the structs means that Cherokee's
	SHA512 operations break SSL handshakes.

Signed-Off-By: Daniel Silverstone <dsilvers@digital-scurf.org>
Merge pull request #1109 from kinnison/kinnison/rename-sha-functions

SHA{1,512}: Rename structs and functions