criu --help: fix --cgroups-props-file

* fix a typo (descrition -> description)
* add a comma before "but"
* remove a period at the end of the sentence

Was:
  --cgroup-props-file FILE
                        same as --cgroup-props but taking descrition
                        from the path specified.

Now:
  --cgroup-props-file FILE
                        same as --cgroup-props, but taking description
                        from the path specified
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

@@ -867,8 +867,8 @@ usage:
 "                        to be checkpointed, which are described\n"
 "                        via STRING using simplified YAML format.\n"
 "  --cgroup-props-file FILE\n"
-"                        same as --cgroup-props but taking descrition\n"
-"                        from the path specified.\n"
+"                        same as --cgroup-props, but taking description\n"
+"                        from the path specified\n"
 "  --cgroup-dump-controller NAME\n"
 "                        define cgroup controller to be dumped\n"
 "                        and skip anything else present in system.\n"