Issue #1679 : Fix build failure due to javadoc
Issue #1679 : Fix build failure due to javadoc

Descriptions of the changes in this PR:



### Motivation

Fix build failure due to javadoc, additionalOptions' type is  an array .
### Changes

correct assignment strategy of additionalOptions to avoid type mismatch

Master Issue: #1679 


Author: songsong <songsong@taovip.com>

Reviewers: Enrico Olivelli <eolivelli@gmail.com>, Sijie Guo <sijie@apache.org>

This closes #1681 from aCoder2013/fix-javadoc-build, closes #1679
apache/bookkeeper,apache/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,apache/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper