Osu: Songs disappear after inconclusive song search

[lanes100]

BUG: just discovered if you type to search for a song, and your search returns no results, all songs disappear even after backspacing. The only way to get the songs to pop back up is to either restart or re-import songs from stable in the main menu.

[FreezyLemon]

This also adds this notification for me:

From runtime.log:

21/03/2018 15:45:04: System.ArgumentNullException: Value cannot be null.
21/03/2018 15:45:04: Parameter name: value
21/03/2018 15:45:04: at osu.Framework.IO.Network.WebRequest.AddParameter(String name, String value) in D:\DEV\Microsoft Visual Studio 2017 Preview\osu\osu-framework\osu.Framework\IO\Network\WebRequest.cs:line 577
21/03/2018 15:45:04: at osu.Game.Online.API.Requests.GetScoresRequest.CreateWebRequest() in D:\DEV\Microsoft Visual Studio 2017 Preview\osu\osu.Game\Online\API\Requests\GetScoresRequest.cs:line 51
21/03/2018 15:45:04: at osu.Game.Online.API.APIRequest.Perform(APIAccess api) in D:\DEV\Microsoft Visual Studio 2017 Preview\osu\osu.Game\Online\API\APIRequest.cs:line 75
21/03/2018 15:45:04: at osu.Game.Online.API.APIAccess.handleRequest(APIRequest req) in D:\DEV\Microsoft Visual Studio 2017 Preview\osu\osu.Game\Online\API\APIAccess.cs:line 201

It seems to stem from this:

Where for some reason, the DummyRulesetInfo.ShortName is shown as null instead of "dummy"...

No clue why this happens though.

[peppy]

The fix I submitted fixes this.