ports/179572: Add option for science/py-h5py to use science/hdf5-18 instead of science/hdf5

[eadler at FreeBSD.org]

Synopsis: Add option for science/py-h5py to use science/hdf5-18 instead of science/hdf5

State-Changed-From-To: feedback->open
State-Changed-By: eadler
State-Changed-When: Sun Jul 14 10:23:12 UTC 2013
State-Changed-Why: 
its been a month since the feedback state - so lets open the PR so it
could be committed

http://www.freebsd.org/cgi/query-pr.cgi?pr=179572