rst: Include criu/include/ptrace.h instead of system one

On ARM some PTRACE_... constants are not declared in sys/ptrace.h file.
They are in linux/ptrace.h, but on x86 this file somewhat conflicts with
the sys/ one. For now fix ARM compilation by using criu/ one and think
of it later.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>