Intended javadoc options are not honored for Java unidoc

project/SparkBuild.scala specifies

javacOptions in doc := Seq(
  "-windowtitle", "Spark " + version.value.replaceAll("-SNAPSHOT", "") + "JavaDoc",
  "-public",
  "-noqualifier", "java.lang"
)

However, sbt javaunidoc:doc ignores these options. To wit, the title of http://spark.apache.org/docs/latest/api/java/index.html is Generated Documentation (Untitled), not Spark 1.6.2 JavaDoc as it should be.

(N.B. the Spark 1.6.2 build defines several javadoc groups as well, which are also missing from the official docs.)