sysctl: no need to check for eof twice

Let's only check for eof once after the fgets(). There's no point in checking
EOF before the first read, and twice in each loop.

src/sysctl/sysctl.c

@@ -104,7 +104,7 @@ static int parse_file(OrderedHashmap *sysctl_options, const char *path, bool ign
         }
 
         log_debug("Parsing %s", path);
-        while (!feof(f)) {
+        for (;;) {
                 char l[LINE_MAX], *p, *value, *new_value, *property, *existing;
                 void *v;
                 int k;