Fix empty "latest" column in GUI.

Closes KSP-CKAN#1296.

Yes, my "tidying" of the code in KSP-CKAN#1295 changed the logic. Ooops!

Thanks to @plague006 for spotting this. :)

GUI/GUIMod.cs

@@ -58,9 +58,6 @@ public GUIMod(Module mod, IRegistryQuerier registry, KSPVersion current_ksp_vers
             Version latest_version = null;
             var ksp_version = mod.ksp_version;
 
-            InstalledVersion = installed_version != null ? installed_version.ToString() : "-";
-            LatestVersion = latest_version != null ? latest_version.ToString() : "-";
-
             try
             {
                 var latest_available = registry.LatestAvailable(mod.identifier, current_ksp_version);
@@ -72,6 +69,9 @@ public GUIMod(Module mod, IRegistryQuerier registry, KSPVersion current_ksp_vers
                 latest_version = installed_version;
             }
 
+            InstalledVersion = installed_version != null ? installed_version.ToString() : "-";
+            LatestVersion = latest_version != null ? latest_version.ToString() : "-";
+
             // Let's try to find the compatibility for this mod. If it's not in the registry at
             // all (because it's a DarkKAN mod) then this might fail.