(F18) sysctl: give files with later names precedence over earlier ones

This restores the sysctl.d precedence rules of v197.

man/sysctl.d.xml

@@ -92,7 +92,7 @@
                 alphabetical order, regardless in which of the
                 directories they reside, to guarantee that a specific
                 configuration file takes precedence over another file
-                with an alphabetically later name, if both files
+                with an alphabetically earlier name, if both files
                 contain the same variable setting.</para>
 
                 <para>If the administrator wants to disable a

src/sysctl/sysctl.c

@@ -306,7 +306,9 @@ int main(int argc, char *argv[]) {
 
                 r = parse_file(sysctl_options, "/etc/sysctl.conf", true);
 
-                STRV_FOREACH(f, files) {
+                /* F18: iterate backwards to preserve v197's behaviour */
+                f = files + strv_length(files) - 1;
+                STRV_FOREACH_BACKWARDS(f, files) {
                         k = parse_file(sysctl_options, *f, true);
                         if (k < 0 && r == 0)
                                 r = k;