Update some version-related constants
Update some version-related constants

Since we are quite close to final RPC and hooks APIs, we update the hooks and
protocol_version constants.

Reviewed-by: imsnah

ganeti/ganeti,apyrgio/snf-ganeti,ganeti-github-testing/ganeti-test-1,mbakke/ganeti,andir/ganeti,bitemyapp/ganeti,bitemyapp/ganeti,leshchevds/ganeti,apyrgio/ganeti,yiannist/ganeti,mbakke/ganeti,ganeti/ganeti,onponomarev/ganeti,andir/ganeti,ganeti/ganeti,apyrgio/ganeti,andir/ganeti,leshchevds/ganeti,dimara/ganeti,yiannist/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,grnet/snf-ganeti,grnet/snf-ganeti,onponomarev/ganeti,leshchevds/ganeti,dimara/ganeti,ganeti-github-testing/ganeti-test-1,yiannist/ganeti