Add a comment after some #endif at end of apps source code.

Reviewed-by: NKurt Roeckx <kurt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1168)

apps/s_client.c

@@ -2684,4 +2684,4 @@ static int ocsp_resp_cb(SSL *s, void *arg)
 }
 # endif
 
-#endif
+#endif  /* OPENSSL_NO_SOCK */

apps/s_server.c

@@ -3304,4 +3304,4 @@ static void free_sessions(void)
     first = NULL;
 }
 
-#endif
+#endif  /* OPENSSL_NO_SOCK */

apps/ts.c

@@ -978,4 +978,4 @@ static int verify_cb(int ok, X509_STORE_CTX *ctx)
 {
     return ok;
 }
-#endif
+#endif  /* ndef OPENSSL_NO_TS */