meson: RC_LOCAL_SCRIPT_PATH_START to RC_LOCAL_PATH

RC_LOCAL_SCRIPT_PATH_START and RC_LOCAL_SCRIPT_PATH_STOP were was originally
added in the conversion to meson based on the autotools name. In
4450894653 RC_LOCAL_SCRIPT_PATH_STOP was dropped.
We don't need to use such a long name.

src/rc-local-generator/rc-local-generator.c

@@ -59,7 +59,7 @@ static int run(const char *dest, const char *dest_early, const char *dest_late)
 
         assert_se(arg_dest = dest);
 
-        if (check_executable(RC_LOCAL_SCRIPT_PATH_START) >= 0) {
+        if (check_executable(RC_LOCAL_PATH) >= 0) {
                 log_debug("Automatically adding rc-local.service.");
 
                 r = add_symlink("rc-local.service", "multi-user.target");