data_transfer: close stream before checking shasum

Else, sometimes the file is not correct and cause an invalid shasum

Change-Id: Ia66bb715331589e1990f0fa7d6ac753187ed2bc1

src/data_transfer.cpp

@@ -203,6 +203,8 @@ IncomingFile::process()
         auto shared = w.lock();
         if (!shared)
             return;
+        if (shared->stream_ && shared->stream_.is_open())
+            shared->stream_.close();
         auto correct = shared->sha3Sum_.empty();
         if (!correct) {
             // Verify shaSum