use standard way to find teh checkum type and really send it to server

will fix missing checksum for bulk upload

will ensure consistent behavior between bulk upload, plain old upload
and chunked upload

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

Author: mgallien

src/libsync/bulkpropagatorjob.cpp

@@ -204,7 +204,7 @@ void BulkPropagatorJob::doStartUpload(SyncFileItemPtr item,
 
     const auto remotePath = propagator()->fullRemotePath(fileToUpload._file);
 
-    currentHeaders["X-File-MD5"] = transmissionChecksumHeader;
+    currentHeaders[checkSumHeaderC] = transmissionChecksumHeader;
 
     BulkUploadItem newUploadFile{propagator()->account(), item, fileToUpload,
                 remotePath, fileToUpload._path,
@@ -295,7 +295,7 @@ void BulkPropagatorJob::slotComputeTransmissionChecksum(SyncFileItemPtr item,
 {
     // Compute the transmission checksum.
     const auto computeChecksum = new ComputeChecksum(this);
-    const auto checksumType = uploadChecksumEnabled() ? "MD5" : "";
+    const auto checksumType = uploadChecksumEnabled() ? propagator()->account()->capabilities().preferredUploadChecksumType() : "";
     computeChecksum->setChecksumType(checksumType);
 
     connect(computeChecksum, &ComputeChecksum::done, this, [this, item, fileToUpload] (const QByteArray &contentChecksumType, const QByteArray &contentChecksum) {