[SPARK-9052] [SPARKR] Fix comments after curly braces

[[SPARK-9052] Fix comments after curly braces - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-9052)

This is the full result of lintr at the rivision:01155162.
[[SPARK-9052] the result of lint-r at the revision:01155162](https://gist.github.com/yu-iskw/e7246041b173a3f29482)

This is the difference of the result between before and after.
https://gist.github.com/yu-iskw/e7246041b173a3f29482/revisions

Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #7440 from yu-iskw/SPARK-9052 and squashes the following commits:

015d738 [Yu ISHIKAWA] Fix the indentations and move the placement of commna
5cc30fe [Yu ISHIKAWA] Fix the indentation in a condition
4ead0e5 [Yu ISHIKAWA] [SPARK-9052][SparkR] Fix comments after curly braces