config.c: fix misspelt "occurred" in an error message

Signed-off-by: NPeter Colberg <peter@colberg.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

config.c

@@ -1278,7 +1278,7 @@ static void git_config_raw(config_fn_t fn, void *data)
 		 * something went really wrong and we should stop
 		 * immediately.
 		 */
-		die(_("unknown error occured while reading the configuration files"));
+		die(_("unknown error occurred while reading the configuration files"));
 }
 
 static void configset_iter(struct config_set *cs, config_fn_t fn, void *data)