boolean rebuildIndex() throws IOException {
		for (File f : root.listFiles()) {
			if (f.isDirectory()) {
				rebuildDirectoryIndex(f);
			}
		}
		if (rebuildErrWriter != null) {
			rebuildErrWriter.close();
			return false;
		}
		return true;
	}
Attempt to parse index version
@param firstIndexLine
@return index version or -1 if index version unknown
Ghidra/Framework/FileSystem/src/main/java/ghidra/framework/store/local/IndexedLocalFileSystem.java