Authenticates before checking for AltServers

This means Auth flow is presented even when AltServer is not nearby.

AltStore/Operations/FindServerOperation.swift

@@ -0,0 +1,51 @@
+//
+//  FindServerOperation.swift
+//  AltStore
+//
+//  Created by Riley Testut on 9/8/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import Foundation
+import Roxas
+
+@objc(FindServerOperation)
+class FindServerOperation: ResultOperation<Server>
+{
+    let group: OperationGroup
+    
+    init(group: OperationGroup)
+    {
+        self.group = group
+        
+        super.init()
+    }
+    
+    override func main()
+    {
+        super.main()
+        
+        if let error = self.group.error
+        {
+            self.finish(.failure(error))
+            return
+        }
+        
+        if let server = ServerManager.shared.discoveredServers.first(where: { $0.isPreferred })
+        {
+            // Preferred server.
+            self.finish(.success(server))
+        }
+        else if let server = ServerManager.shared.discoveredServers.first
+        {
+            // Any available server.
+            self.finish(.success(server))
+        }
+        else
+        {
+            // No servers.
+            self.finish(.failure(ConnectionError.serverNotFound))
+        }
+    }
+}
+