core: simplify get_process_umask() invocation

src/core/unit.c

@@ -207,7 +207,7 @@ static void unit_init(Unit *u) {
                         /* User manager might have its umask redefined by PAM or UMask=. In this
                          * case let the units it manages inherit this value by default. They can
                          * still tune this value through their own unit file */
-                        (void) get_process_umask(getpid_cached(), &ec->umask);
+                        (void) get_process_umask(0, &ec->umask);
                 }
         }