restore: move pid variable to local scope

cr-restore.c:1516:9: warning: Value stored to 'pid' during its initialization is never read
                pid_t pid = item->pid.real;
                      ^~~   ~~~~~~~~~~~~~~
cr-restore.c:1570:9: warning: Value stored to 'pid' during its initialization is never read
                pid_t pid = item->pid.real;
                      ^~~   ~~~~~~~~~~~~~~

Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>