We add a cluster feature that informs whether the xxHash algorithm is
supported, and allow nodes to switch to it. We use a cluster feature
because older versions are not ready to receive a different digest
algorithm than MD5 when answering a data request.
If we ever should add a new hash algorithm, we would also need to
add a new cluster feature for that algorithm. The alternative would be
to add code so a coordinator could negotiate what digest algorithm to
use with the set of replicas it is contacting.
Fixes#2884
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
0bab3e59c2