fix cancel download

Signed-off-by: marinofaggiana <ios@nextcloud.com>

iOSClient/Utility/ParallelWorker.swift

@@ -56,6 +56,8 @@ class ParallelWorker {
             hud.detailTextLabel.text = NSLocalizedString("_tap_to_cancel_", comment: "")
             hud.tapOnHUDViewBlock = { hud in
                 self.isCancelled = true
+                // Cancel all download
+                NCNetworking.shared.cancelAllDownloadTransfer()
                 hud.dismiss()
             }
             self.hud = hud