criu --help: improve --manage-cgroup description

* fix a typo (usig)
* slightly rephrased
* remove a period at the end
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/crtools.c

@@ -856,8 +856,8 @@ usage:
 "                        allow autoresolving mounts with external sharing\n"
 "  --enable-external-masters\n"
 "                        allow autoresolving mounts with external masters\n"
-"  --manage-cgroups [m]  dump or restore cgroups the process is in usig mode:\n"
-"                        'none', 'props', 'soft' (default), 'full' and 'strict'.\n"
+"  --manage-cgroups [m]  dump/restore process' cgroups; argument can be one of\n"
+"                        'none', 'props', 'soft' (default), 'full' or 'strict'\n"
 "  --cgroup-root [controller:]/newroot\n"
 "                        change the root cgroup the controller will be\n"
 "                        installed into. No controller means that root is the\n"