Fixing RavenDB-1499 (2nd attempt)

Something went wrong with my local git repo, so I had to redo it. This is the same code changes as https://github.com/ayende/ravendb/pull/492, so you can ignore that one.

BTW, I get quite a few OWIN errors when running ClientServer tests is this branch:
```
System.MissingMemberException : The server factory could not be located for the given input: Microsoft.Owin.Host.HttpListener
Stack Trace:
   at Microsoft.Owin.Hosting.Engine.HostingEngine.ResolveServerFactory(StartContext context)
   at Microsoft.Owin.Hosting.Engine.HostingEngine.Start(StartContext context)
   at Microsoft.Owin.Hosting.WebApp.StartImplementation(IServiceProvider services, StartOptions options, Action`1 startup)
   at Microsoft.Owin.Hosting.WebApp.Start(String url, Action`1 startup)
   at Raven.Database.Server.OwinHttpServer..ctor(InMemoryRavenConfiguration config) in c:\Users\Matt\Documents\GitHub\ravendb\Raven.Database\Server\OwinHttpServer.cs:line 23
   at Raven.Server.RavenDbServer..ctor(InMemoryRavenConfiguration configuration) in c:\Users\Matt\Documents\GitHub\ravendb\Raven.Server\RavenDbServer.cs:line 34
   at Raven.Tests.Helpers.RavenTestBase.GetNewServer(Int32 port, String dataDirectory, Boolean runInMemory, String requestedStorage, Boolean enableAuthentication, String activeBundles) in c:\Users\Matt\Documents\GitHub\ravendb\Raven.Tests.Helpers\RavenTestBase.cs:line 196
   at Raven.Tests.Helpers.RavenTestBase.NewRemoteDocumentStore(Boolean fiddler, RavenDbServer ravenDbServer, String databaseName, Boolean runInMemory, String dataDirectory, String requestedStorage, Boolean enableAuthentication) in c:\Users\Matt\Documents\GitHub\ravendb\Raven.Tests.Helpers\RavenTestBase.cs:line 127
   at Raven.Bundles.Tests.UniqueConstraints.Bugs.TroyMapReduce.UsingRemote() in c:\Users\Matt\Documents\GitHub\ravendb\Bundles\Raven.Bundles.Tests\UniqueConstraints\Bugs\TroyMapReduce.cs:line 59
```