cql: Allow user manipulation queries to use cql keywords for a name
cql: Allow user manipulation queries to use cql keywords for a name

This commit allows the CREATE/DROP/ALTER USER cql queris
to use cql keywords for the user name (for example "empty").

Signed-off-by: Eliran Sinvani <da50580cbf194fc955df7e548082c96276f28b37@scylladb.com>
Message-Id: <20190612104301.8322-1-da50580cbf194fc955df7e548082c96276f28b37@scylladb.com>

scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla