java/eclipse: Remove troublesome comment completely
Freshports won't update the entry due to choking on the MAVEN_OPTS
comment. Truthfully the comment is more trouble than it's worth. First,
it's MVN_OPTS, not MAVEN_OPTS. Secondly, "+=" is a no-op, so the
definition should be there anyway. Thirdly, MVN_OPTS is undefined.
Just remove the whole mess.