If the content server client fails to open a storage session, keep retrying.

This behavior matches hldsupdatetool.

DepotDownloader/ContentDownloader.cs

@@ -14,6 +14,7 @@ namespace DepotDownloader
     static class ContentDownloader
     {
         const string DEFAULT_DIR = "depots";
+        const int STORAGE_RETRY_COUNT = 500;
 
         static Steam3Session steam3;
 
@@ -165,23 +166,29 @@ namespace DepotDownloader
 
             ContentServerClient csClient = new ContentServerClient();
 
-            csClient.Connect( contentServer );
-
-
             ContentServerClient.StorageSession session = null;
+            int retryCount = 0;
+
+            while ( session == null )
+            {
                 try
                 {
+                    csClient.Connect( contentServer );
                     session = csClient.OpenStorage( ( uint )depotId, ( uint )depotVersion, ( uint )cellId, credentials );
                 }
                 catch ( Steam2Exception ex )
                 {
-                Console.WriteLine( "Unable to open storage: " + ex.Message );
+                    csClient.Disconnect();
+                    retryCount++;
 
+                    if (retryCount > STORAGE_RETRY_COUNT)
+                    {
                         if (steam3 != null)
                             steam3.Disconnect();
-
                         return;
                     }
+                }
+            }
 
             using ( session )
             {