Tweak of the platform_specific.mk.x86_64-linux in PyFerret to try both the lib64 and lib directories for finding libpyferret.so
Tweak of the platform_specific.mk.x86_64-linux in PyFerret to try both the lib64 and lib directories for finding libpyferret.so

git-svn-id: 77c6ae948ca0f9b1480c5330e5e23bcf0afa938f@14560 fdbf22ae-c210-0410-be80-ca943da6b8f8

NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret