auth-filter: pass url with query string attached

Otherwise redirections come out wrong.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff --git a/cgit.c b/cgit.c
index 6301b87..2f07e6d 100644
--- a/cgit.c
+++ b/cgit.c
@@ -645,7 +645,7 @@
 		ctx.env.https ? ctx.env.https : "",
 		ctx.qry.repo ? ctx.qry.repo : "",
 		ctx.qry.page ? ctx.qry.page : "",
-		ctx.qry.url ? ctx.qry.url : "",
+		cgit_currentfullurl(),
 		cgit_loginurl());
 }