SBUS: Fix warning declaration shadows a global declaration
src/sbus/sssd_dbus_meta.c: In function 'sbus_meta_find_signal':
src/sbus/sssd_dbus_meta.c:43: warning: declaration of 'signal' shadows a global
declaration
/usr/include/signal.h:101: warning: shadowed declaration is here
Reviewed-by: Stef Walter <stefw@redhat.com>
(cherry picked from commit e998f7e52cea5344f12a444761cb2d9cc6b00007)