Add zsh completion for 'docker daemon --no-legacy-registry'

Signed-off-by: Steve Durrheimer <s.durrheimer@gmail.com>

contrib/completion/zsh/_docker

@@ -452,6 +452,7 @@ __docker_subcommand() {
                 "($help)--log-driver=-[Default driver for container logs]:Logging driver:(json-file syslog journald gelf fluentd awslogs none)" \
                 "($help)*--log-opt=-[Log driver specific options]:log driver options: " \
                 "($help)--mtu=-[Set the containers network MTU]:mtu:(0 576 1420 1500 9000)" \
+                "($help)--no-legacy-registry[Do not contact legacy registries]" \
                 "($help -p --pidfile)"{-p,--pidfile=-}"[Path to use for daemon PID file]:PID file:_files" \
                 "($help)*--registry-mirror=-[Preferred Docker registry mirror]:registry mirror: " \
                 "($help -s --storage-driver)"{-s,--storage-driver=-}"[Storage driver to use]:driver:(aufs devicemapper btrfs zfs overlay)" \