Handle EC2 instances with multiple network interfaces (#4766)

Currently instances with multiple ENI's can't be started or stopped
because sourceDestCheck is a per-interface attribute, but we use the
boto global access to it (which only works when there's a single ENI).

This patch handles multiple ENI's and applies the sourcedestcheck across
all interfaces the same way.

Fixes #3234

cloud/amazon/ec2.py

@@ -1310,9 +1310,22 @@ def startstop_instances(module, ec2, instance_ids, state, instance_tags):
         for inst in res.instances:
 
             # Check "source_dest_check" attribute
+            try:
                 if inst.vpc_id is not None and inst.get_attribute('sourceDestCheck')['sourceDestCheck'] != source_dest_check:
                     inst.modify_attribute('sourceDestCheck', source_dest_check)
                     changed = True
+            except boto.exception.EC2ResponseError as exc:
+                # instances with more than one Elastic Network Interface will
+                # fail, because they have the sourceDestCheck attribute defined
+                # per-interface
+                if exc.code == 'InvalidInstanceID':
+                    for interface in inst.interfaces:
+                        if interface.source_dest_check != source_dest_check:
+                            ec2.modify_network_interface_attribute(interface.id, "sourceDestCheck", source_dest_check)
+                            changed = True
+                else:
+                    module.fail_json(msg='Failed to handle source_dest_check state for instance {0}, error: {1}'.format(inst.id, exc),
+                                     exception=traceback.format_exc(exc))
 
             # Check "termination_protection" attribute
             if inst.get_attribute('disableApiTermination')['disableApiTermination'] != termination_protection: