Change in the approach: do not ignore anymore javadoc build failure.
Instead reduce the amount of checks. We make this change because the
previous approach were leaving temporary files in the javadoc directory.
The inconvenient is that we lost warnings about invalid HTML or references.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK8@1588555 13f79535-47bb-0310-9956-ffa450edef68