Don't install the Java shmem tools if we aren't building Java support.

Thanks to Paul Hargrove for noticing.

Taken from open-mpi/ompi@064a241145d7384ca8d759c5ef41261d0f242e94

@jsquyres please comment
Why would it be `#if` instead of `if`?  This is an automake conditional, right?

http://www.gnu.org/software/automake/manual/html_node/Usage-of-Conditionals.html#Usage-of-Conditionals