Handle portbindings with no local_link_information gracefully

We were assuming that all ports with binding::profiles would have
local_link_information. This assumption is incorrect, so we should
handle such ports gracefully rather than throwing a KeyError.

Change-Id: Id73e43199c933bc7eb6e71f75d4e6f04cce6c091

networking_arista/ml2/mechanism_arista.py

@@ -657,7 +657,7 @@ class AristaDriver(driver_api.MechanismDriver):
         binding_profile = port['binding:profile']
         bindings = []
         if binding_profile:
-            bindings = binding_profile['local_link_information']
+            bindings = binding_profile.get('local_link_information', [])
 
         port_id = port['id']
         port_name = port['name']
@@ -818,7 +818,7 @@ class AristaDriver(driver_api.MechanismDriver):
         binding_profile = port['binding:profile']
         switch_bindings = []
         if binding_profile:
-            switch_bindings = binding_profile['local_link_information']
+            switch_bindings = binding_profile.get('local_link_information', [])
         sg = port['security_groups']
 
         if not device_id or not host: