Fix "Remove Last Capture"

git-svn-id: svn://localhost/ardour2/trunk@1692 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/audiofilesource.cc

@@ -248,7 +248,10 @@ AudioFileSource::set_state (const XMLNode& node)
 void
 AudioFileSource::mark_for_remove ()
 {
-	if (!writable()) {
+	// This operation is not allowed for sources for destructive tracks or embedded files.
+	// Fortunately mark_for_remove() is never called for embedded files. This function
+	// must be fixed if that ever happens.
+	if (_flags & Destructive) {
 		return;
 	}