printers.putAll(...) clears NativePrinterMap

[tresf]

As identified in #1124 by @Vzor-, printers.putAll(...) will wipe out all entries of NativePrinterMap.

tray/src/qz/printer/PrintServiceMatcher.java

Lines 54 to 57 in 402f924

	NativePrinterMap printers = NativePrinterMap.getInstance();
	if (!printers.contains(defaultService)) {
	printers.putAll(defaultService);
	}

This is because NativePrinterMap.findMissing(...) performs a destructive operation:

tray/src/qz/printer/info/NativePrinterMap.java

Lines 46 to 64 in 402f924

	public ArrayList<PrintService> findMissing(PrintService[] services) {
	ArrayList<PrintService> serviceList = new ArrayList<>(Arrays.asList(services)); // shrinking list drastically improves performance
	for(NativePrinter printer : values()) {
	if (serviceList.contains(printer.getPrintService())) {
	serviceList.remove(printer.getPrintService()); // existing match
	} else {
	printer.setOutdated(true); // no matches, mark to be removed
	}
	}
	// remove outdated
	for (Map.Entry<String, NativePrinter> entry : entrySet()) {
	if(entry.getValue().isOutdated()) {
	remove(entry.getKey());
	}
	}
	// any remaining services are new/missing
	return serviceList;
	}

[tresf]

This will be fixed by #1124, specifically a8beeba.