[rygel] server: Prevent critical on upload

[Jens Georg <jensgeorg src gnome org>]

commit c9c0a38f09eaf9933d3450b64ede387d4929845b
Author: Jens Georg <jensg openismus com>
Date:   Mon Mar 25 13:31:05 2013 +0100

    server: Prevent critical on upload

 src/librygel-server/rygel-client-hacks.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/librygel-server/rygel-client-hacks.vala b/src/librygel-server/rygel-client-hacks.vala
index d1cf04d..c6b53be 100644
--- a/src/librygel-server/rygel-client-hacks.vala
+++ b/src/librygel-server/rygel-client-hacks.vala
@@ -107,7 +107,7 @@ internal abstract class Rygel.ClientHacks : GLib.Object {
         var headers = message.request_headers;
 
         var agent = headers.get_one ("User-Agent");
-        if (agent == null) {
+        if (agent == null && client_agent_cache != null) {
             var address = message.get_address ();
             agent = client_agent_cache.get (address.get_physical ());
         }