Add suspend option to in dummy plugin

[cosmo0920]

No description provided.

[tagomoris]

Please leave storage_local as is, because these code will be fixed once more with plugin id auto-configuration (with root path by system config)

[tagomoris]

And, could you rebase changes of in_dummy on current master?

[cosmo0920]

I've rebased with current master.
But suspend option related tests didn't pass yet.

[cosmo0920]

Please leave storage_local as is, because these code will be fixed once more with plugin id auto-configuration (with root path by system config)

Oh.... I think almost storage_local code should be leave as-is. But this line https://github.com/fluent/fluentd/pull/900/files#diff-0380de12f73675c40904702aab31701cR61 should be fixed because without this fix I always got the following error:

================================================================================
Error: test: value of auto increment key is suspended after stop-and-start(DummyTest::suspend internal counters if suspend is true): Fluent::ConfigError: Directory is not writable for plugin storage file 'test/tmp/in_dummy/store/json'
/home/hhatake/Github/fluentd/lib/fluent/plugin/storage_local.rb:61:in `configure'
/home/hhatake/Github/fluentd/lib/fluent/plugin_helper/storage.rb:92:in `block in configure'
/home/hhatake/Github/fluentd/lib/fluent/plugin_helper/storage.rb:87:in `each'
/home/hhatake/Github/fluentd/lib/fluent/plugin_helper/storage.rb:87:in `configure'
/home/hhatake/Github/fluentd/lib/fluent/plugin/in_dummy.rb:61:in `configure'
/home/hhatake/Github/fluentd/lib/fluent/test/driver/base.rb:78:in `configure'
test/plugin/test_in_dummy.rb:12:in `create_driver'
test/plugin/test_in_dummy.rb:163:in `block (2 levels) in <class:DummyTest>'
================================================================================

[tagomoris]

It's time to revoke this thread, and there is just a point to be fixed after many fixes during pending time.
@cosmo0920 Could you see my review comment (following this comment)?

[tagomoris]

Rebase this tree on master, and please use default_type instead of type keyword argument.

[cosmo0920]

OK. I'll try your suggested changes within a week.

[tagomoris]

LGTM!

[cosmo0920]

Thanks!!!