Exception in senza create witout senza init

[Petr Gladkikh]

senza throws exception when security group is missing. It can check this condition and suggest using "senza init" to create the group.

EXCEPTION OCCURRED: Security Group "app-something" does not exist
Unknown Error: Security Group "app-something" does not exist.

Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/senza/error_handling.py", line 104, in __call__
    self.function(*args, **kwargs)
  File "/home/someuser/.local/lib/python3.5/site-packages/click/core.py", line 716, in __call__
    return self.main(*args, **kwargs)
  File "/home/someuser/.local/lib/python3.5/site-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/home/someuser/.local/lib/python3.5/site-packages/click/core.py", line 1060, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/someuser/.local/lib/python3.5/site-packages/click/core.py", line 889, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/someuser/.local/lib/python3.5/site-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/senza/cli.py", line 576, in create
    data = create_cf_template(definition, region, version, parameter, force, parameter_file)
  File "/usr/local/lib/python3.5/dist-packages/senza/cli.py", line 659, in create_cf_template
    data = evaluate(definition.copy(), args, account_info, force)
  File "/usr/local/lib/python3.5/dist-packages/senza/cli.py", line 238, in evaluate
    definition = componentfn(definition, configuration, args, info, force, account_info)
  File "/usr/local/lib/python3.5/dist-packages/senza/components/taupage_auto_scaling_group.py", line 81, in component_taupage_auto_scaling_group
    definition = component_auto_scaling_group(definition, configuration, args, info, force, account_info)
  File "/usr/local/lib/python3.5/dist-packages/senza/components/auto_scaling_group.py", line 99, in component_auto_scaling_group
    resolve_security_groups(configuration["SecurityGroups"], args.region)
  File "/usr/local/lib/python3.5/dist-packages/senza/aws.py", line 126, in resolve_security_groups
    result.append(resolve_security_group(security_group, region))
  File "/usr/local/lib/python3.5/dist-packages/senza/aws.py", line 119, in resolve_security_group
    raise ValueError('Security Group "{}" does not exist'.format(security_group))
ValueError: Security Group "app-something" does not exist