parasite-syscall: print syscall number as %lu

We will still able to distinguish if it's garbage in ax register, but
this is definitely prettier:
(00.036900) 687 was trapped
(00.036903) 687 is going to execute the syscall 158
(00.036928) 687 was trapped
(00.036931) 687 is going to execute the syscall 173

Than that:
(00.024403) 687 was trapped
(00.024407) 687 is going to execute the syscall 9e
(00.024419) 687 was trapped
(00.024421) 687 is going to execute the syscall ad
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/parasite-syscall.c

@@ -974,7 +974,7 @@ int parasite_stop_on_syscall(int tasks, const int sys_nr, enum trace_flags trace
 			return -1;
 		}
 
-		pr_debug("%d is going to execute the syscall %lx\n", pid, REG_SYSCALL_NR(regs));
+		pr_debug("%d is going to execute the syscall %lu\n", pid, REG_SYSCALL_NR(regs));
 		if (REG_SYSCALL_NR(regs) == sys_nr) {
 			/*
 			 * The process is going to execute the required syscall,