nginx: be more flexible when handling full-uid --searches

This addresses the final bit of #94.

It is concretely useful for fielding queries like:

    gpg --search '=Alice Jones <alice@example.net>'

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>

hagrid-routes.conf

@@ -87,7 +87,7 @@ location /pks/lookup {
     # strip angle brackets - we don't need them, but they cause issues
     # with the Rocket framework
     # see https://gitlab.com/sequoia-pgp/hagrid/issues/94
-    if ($request_uri ~ "^/pks/lookup\?(.*)\<(.+)\>(.*)") {
+    if ($request_uri ~ "^/pks/lookup\?(.*search=)[^&<>]*\<(.+)\>(.*)") {
         set $left $1;
         set $middle $2;
         set $right $3;