in case of a case clash, verify also once the file is downloaded

it could be that when starting the download job, no conflict would
exists but when receiving the file, a conflict would know exists

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

src/libsync/propagatedownload.cpp

@@ -1146,7 +1146,12 @@ void PropagateDownloadFile::downloadFinished()
         qCWarning(lcPropagateDownload()) << "invalid modified time" << _item->_file << _item->_modtime;
     }
 
-    bool previousFileExists = FileSystem::fileExists(filename);
+    if (propagator()->localFileNameClash(_item->_file)) {
+        _item->_instruction = CSYNC_INSTRUCTION_CASE_CLASH_CONFLICT;
+        qCInfo(lcPropagateDownload) << "setting instruction to" << _item->_instruction << _item->_file;
+    }
+
+    bool previousFileExists = FileSystem::fileExists(filename) && _item->_instruction != CSYNC_INSTRUCTION_CASE_CLASH_CONFLICT;
     if (previousFileExists) {
         // Preserve the existing file permissions.
         QFileInfo existingFile(filename);