Fix copy for multi-account/regions case

[zhirafovod]

distami was failing with the following error running with multiple accounts/regiond:

distami ami-12345678 --accounts=111111111111,222222222222 --non-public -v --to us-east-1,ap-northeast-1 -v -p

was failing with an error like a one below:

2016-10-11 00:33:40 [INFO] Sharing AMI ami-12345678 with AWS Accounts 111111111111,222222222222
Traceback (most recent call last):
  File "/usr/local/bin/distami", line 9, in <module>
    load_entry_point('distami==1.0.7', 'console_scripts', 'distami')()
  File "/usr/local/lib/python2.7/dist-packages/distami/cli.py", line 132, in run
    copy([distami, region, args])
  File "/usr/local/lib/python2.7/dist-packages/distami/cli.py", line 54, in copy
    distami.share_ami_with_accounts(args.accounts)
  File "/usr/local/lib/python2.7/dist-packages/distami/core.py", line 87, in share_ami_with_accounts
    res = self._image.set_launch_permissions(user_ids=account_ids)
  File "/usr/local/lib/python2.7/dist-packages/boto/ec2/image.py", line 353, in set_launch_permissions
    dry_run=dry_run)
  File "/usr/local/lib/python2.7/dist-packages/boto/ec2/connection.py", line 519, in modify_image_attribute
    return self.get_status('ModifyImageAttribute', params, verb='POST')
  File "/usr/local/lib/python2.7/dist-packages/boto/connection.py", line 1226, in get_status
    raise self.ResponseError(response.status, response.reason, body)
boto.exception.EC2ResponseError: EC2ResponseError: 400 Bad Request
<?xml version="1.0" encoding="UTF-8"?>
<Response><Errors><Error><Code>InvalidAMIAttributeItemValue</Code><Message>Invalid attribute item value "111111111111,222222222222 " for userId item type.</Message></Error></Errors><RequestID><REDACTED></RequestID></Response>

Minor changes: Updated zones in unittests to reflect new zones introduced by AWS