Deprecate or remove old-style conditionals now that branches are
supported in the logtash config.

Config settings existing in 1.1.13 and prior were marked deprecated.
Settings that have not been released were deleted (such as fields,
include_fields, etc).

I am so excited for conditionals.

Instead of:
  filter { grok { type => foo ... } }

You now do:
  filter {
    if [type] == "foo" {
      grok { ... }
      ...
    }
  }