Bug in handling SES limit check for non-supported region

[bergkampsliew]

Related to the fix under issue #375
I realised that @jantman has added PR (which is great idea) on top of my fix. However, I think there's a bug which returned boto exception doesn't contain property "Message" -> ex.response['Error']['Message']
(https://github.com/jantman/awslimitchecker/blob/master/awslimitchecker/services/ses.py#L74)
Hence, exception is thrown and uncaught again.

Version

6.0.1
(and reproducible using develop branch)

Installation Method

pip, without virtualenv

Supporting Software Versions

python 2.7.9
(and also python 3.5.3 when testing with develop branch)

Actual Output

when running command awslimitchecker --region eu-central-1, below exception wasn't handled with stacktrace output.

WARNING:awslimitchecker.services.ses:Skipping SES: An error occurred (AccessDenied) when calling the GetSendQuota operation: Unknown
Traceback (most recent call last):
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/services/ses.py", line 67, in find_usage
    resp = self.conn.get_send_quota()
  File "/root/awslimitchecker/lib/python3.5/site-packages/botocore/client.py", line 357, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/root/awslimitchecker/lib/python3.5/site-packages/botocore/client.py", line 661, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (AccessDenied) when calling the GetSendQuota operation: Unknown

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./awslimitchecker", line 11, in <module>
    load_entry_point('awslimitchecker', 'console_scripts', 'awslimitchecker')()
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/runner.py", line 415, in console_entry_point
    r.console_entry_point()
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/runner.py", line 409, in console_entry_point
    res = self.check_thresholds()
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/runner.py", line 310, in check_thresholds
    service=self.service_name)
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/checker.py", line 554, in check_thresholds
    tmp = cls.check_thresholds()
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/services/base.py", line 272, in check_thresholds
    self.find_usage()
  File "/root/awslimitchecker/src/awslimitchecker/awslimitchecker/services/ses.py", line 74, in find_usage
    ex.response['Error']['Message'] == 'Unknown'
KeyError: 'Message'

Expected Output

awslimitchecker gracefully handle the exception and only print short message together with the returned reason from AWS API , without stacktrace.

TrustedAdvisor

Testing Assistance

will make a PR after tested locally

[jantman]

This has been released as 6.1.1 and is now live on PyPI. Thanks so much!