Fix OSS build break in online_formatter
Fix OSS build break in online_formatter

Summary:
The previous diff D32874954 (https://github.com/facebookincubator/ktfmt/commit/c718b535386ceadbd2907a9f3fe64f4d7906f87a) fixed one build break but revealed another.

This time I figured out how to actually build with Maven/Gradle and verified that everything builds okay with the following commands:

```
echo "Building ktfmt with Maven..." \
  && mvn install \
  && cd online_formatter \
  && echo "Building online_formatter with Gradle..." \
  && ./gradlew build \
  && echo "Building ktfmt_idea_plugin with Gradle..." \
  && cd ../ktfmt_idea_plugin \
  && ./gradlew build \
  && echo "Success" \
  || echo "Failure"
```

Reviewed By: strulovich

Differential Revision: D32905040

fbshipit-source-id: ec067e8c863ce770d8e535496dced7ad5149b69f

facebookincubator/ktfmt,facebookincubator/ktfmt,facebookincubator/ktfmt,facebookincubator/ktfmt,facebookincubator/ktfmt