Revert "Haiku have libmtp and libusb, so use them!"

Dbus problems, maybe later.

This reverts commit 9901e4b05e.

src/calibre/constants.py

@@ -168,7 +168,7 @@ class Plugins(collections.Mapping):
             plugins.extend(['winutil', 'wpd', 'winfonts'])
         if isosx:
             plugins.append('usbobserver')
-        if islinux or isosx or ishaiku:
+        if islinux or isosx:
             plugins.append('libusb')
             plugins.append('libmtp')
         self.plugins = frozenset(plugins)