Fix free space reporting for WMDM and MTP

src/devices/mtpdevice.cpp

@@ -138,6 +138,8 @@ void MtpDevice::FinishCopy(bool success) {
   connection_.reset();
 
   db_busy_.unlock();
+
+  ConnectedDevice::FinishCopy(success);
 }
 
 void MtpDevice::StartDelete() {

src/devices/wmdmdevice.cpp

@@ -181,6 +181,8 @@ void WmdmDevice::FinishCopy(bool success) {
   thread_.reset();
 
   db_busy_.unlock();
+
+  ConnectedDevice::FinishCopy(success);
 }
 
 void WmdmDevice::StartDelete() {