lib/model: Consistently show folder description in startup messages

Since we anyway need the folderConfig for this I'm skipping the copying
of all it's attributes that rwfolder did and just keeping the original
around instead.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3825

lib/model/rwfolder_test.go

@@ -322,6 +322,7 @@ func TestWeakHash(t *testing.T) {
 	go fo.copierRoutine(copyChan, pullChan, finisherChan)
 
 	// Test 1 - no weak hashing, file gets fully repulled (`expectBlocks` pulls).
+	fo.DisableWeakHash = true
 	fo.handleFile(desiredFile, copyChan, finisherChan)
 
 	var pulls []pullBlockState
@@ -349,7 +350,7 @@ func TestWeakHash(t *testing.T) {
 	}
 
 	// Test 2 - using weak hash, expectPulls blocks pulled.
-	fo.useWeakHash = true
+	fo.DisableWeakHash = false
 	fo.handleFile(desiredFile, copyChan, finisherChan)
 
 	pulls = pulls[:0]