dirauth: Fix typo in flag relay assignment token

Unfortunately, we wanted to be able to control the Guard flag here but the
token used mentionned "exit" instead.

Oh well, s*** happens :).

Fixes #41035

Signed-off-by: David Goulet <dgoulet@torproject.org>

changes/ticket41035

+  o Minor bugfix (dirauth):
+    - Fix typo in flag assignment approved-routers file. Fixes bug 41035; bugfix
+      on 0.4.8.15

src/feature/dirauth/process_descs.c

@@ -228,7 +228,7 @@ dirserv_load_fingerprint_file(void)
         add_status = RTR_INVALID;
     }  else if (!strcasecmp(nickname, "!middleonly")) {
         add_status = RTR_MIDDLEONLY;
-    } else if (!strcasecmp(nickname, "!stripexit")) {
+    } else if (!strcasecmp(nickname, "!stripguard")) {
         add_status = RTR_STRIPGUARD;
     } else if (!strcasecmp(nickname, "!striphsdir")) {
         add_status = RTR_STRIPHSDIR;