ignore exception if instance doesn't exist in terminate

Sometimes EC2 failed to create an instance, the instance can't be available.
Problem occurred if our code tries to terminate the instance.

Traceback (most recent call last):
  File "/usr/lib64/python2.7/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/lib/python2.7/site-packages/avocado_ec2/ec2_wrapper.py", line 46, in clean_aws_resources_atexit
    instance.terminate()
  File "/usr/lib/python2.7/site-packages/boto3/resources/factory.py", line 455, in do_action
    response = action(self, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/boto3/resources/action.py", line 79, in __call__
    response = getattr(parent.meta.client, operation_name)(**params)
  File "/usr/lib/python2.7/site-packages/botocore/client.py", line 310, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/usr/lib/python2.7/site-packages/botocore/client.py", line 395, in _make_api_call
    raise ClientError(parsed_response, operation_name)
ClientError: An error occurred (InvalidInstanceID.NotFound) when calling the TerminateInstances operation: The instance ID 'i-0d0210cadfabc6eba' does not exist

Signed-off-by: Amos Kong <[email protected]>

avocado_ec2/ec2_wrapper.py

@@ -17,6 +17,7 @@
 import logging
 
 import boto3
+from botocore.exceptions import ClientError
 
 try:
     from botocore.vendored.requests.packages.urllib3.contrib.pyopenssl import extract_from_urllib3
@@ -43,7 +44,11 @@ def clean_aws_resources_atexit():
     global EC2_KEYPAIR_WRAPPERS
 
     for instance in EC2_INSTANCES:
-        instance.terminate()
+        try:
+            instance.terminate()
+        except ClientError as e:
+            if not 'InvalidInstanceID.NotFound' in e.message:
+                raise
 
     for key_pair in EC2_KEYPAIR_WRAPPERS:
         key_pair.destroy()