In my case, upstream builds zookeeper-VERSION.jar but also
zookeeper-VERSION-CONTRIB.jar so jh_installlibs works fine for the first
case but no for the latter.
I propose to introduce a second, optional column in .jlibs which
indicates the desired final name of the jar. There won't be an automatic
solution for all the creativity of upstream.
However we should doublecheck with mh_installjar so that .jlibs could
become a file format for a merge of mh_installjar and jh_installlibs.