Deprecation warning if using nil

[kentarosasaki]

chef-client: 12.11.18
OS: CentOS 7.2

When using this cookbook on CentOS 7.2, you get the following deprecation warning.

[2016-09-09T14:48:34+09:00] WARN: Default value nil is invalid for property resample_every of resource influxdb_continuous_query. Possible fixes: 1.
 Remove 'default: nil' if nil means 'undefined'. 2. Set a valid default value if there is a reasonable one. 3. Allow nil as a valid value of your property (for example, 'property :r
esample_every, [ String, nil ], default: nil'). Error: Property resample_every must be one of: String!  You passed nil. at /var/chef/cache/cookbooks/influxdb/resources/continuous_qu
ery.rb:8:in `class_from_file'