ifupdown: add new ifupdownflags class to carry ifupdown flags

Ticket: cleanup
Reviewed By:
Testing Done: Tested ifupdown sanity

This gets rid of some ugly previous flag handling which was
passed through modules. This creates a global instance of
flags that all addon modules and helper modules can use.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>

addons/ethtool.py

@@ -241,7 +241,7 @@ class ethtool(moduleBase,utilsBase):
 
     def _init_command_handlers(self):
         if not self.ipcmd:
-            self.ipcmd = iproute2(**self.get_flags())
+            self.ipcmd = iproute2()
 
     def run(self, ifaceobj, operation, query_ifaceobj=None, **extra_args):
         """ run ethtool configuration on the interface object passed as