Make database transaction explicit

Signal/src/Loki/View Controllers/DeviceLinkingModal.swift

@@ -184,15 +184,17 @@ final class DeviceLinkingModal : Modal, DeviceLinkingSessionDelegate {
         let signedDeviceLink = DeviceLink(between: master, and: deviceLink.slave)
         LokiFileServerAPI.addDeviceLink(signedDeviceLink).done(on: DispatchQueue.main) { [weak self] in
             SSKEnvironment.shared.messageSender.send(linkingAuthorizationMessage, success: {
-                let hexEncodedPublicKey = deviceLink.slave.hexEncodedPublicKey
-                let thread = TSContactThread.getOrCreateThread(contactId: hexEncodedPublicKey)
-                thread.save()
+                let storage = OWSPrimaryStorage.shared()
+                let slaveHexEncodedPublicKey = deviceLink.slave.hexEncodedPublicKey
+                storage.dbReadWriteConnection.readWrite { transaction in
+                    let thread = TSContactThread.getOrCreateThread(withContactId: slaveHexEncodedPublicKey, transaction: transaction)
+                    thread.save(with: transaction)
+                }
                 let _ = SSKEnvironment.shared.syncManager.syncAllContacts()
                 let _ = SSKEnvironment.shared.syncManager.syncAllGroups()
                 let _ = SSKEnvironment.shared.syncManager.syncAllOpenGroups()
-                let storage = OWSPrimaryStorage.shared()
                 storage.dbReadWriteConnection.readWrite { transaction in
-                    storage.setFriendRequestStatus(.friends, for: hexEncodedPublicKey, transaction: transaction)
+                    storage.setFriendRequestStatus(.friends, for: slaveHexEncodedPublicKey, transaction: transaction)
                 }
                 DispatchQueue.main.async {
                     self?.dismiss(animated: true, completion: nil)