[Development] Deprecate the Keccak hashes in QCryptographicHash?

[Thiago Macieira]

We have them because we made a mistake when we added SHA3 support. We've kept 
them for compatibility, for people who had hashes to compare to and had 
accidentally used Keccak.

They're the only ones we couldn't fall back to Linux's AF_ALG or OpenSSL's 
support, which often contain more optimised code that ours.
-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel System Software Products