Broken build, can't link due to undefined reference to `nc_set_log_level`

It appears that https://github.com/Unidata/netcdf-fortran/pull/44 introduced an issue; see http://my.cdash.org/viewBuildError.php?buildid=919385 for details.  

It's odd that the docker image didn't catch this; the travis.ci config file needs to be updated.  Running it manually exposes the failure as expected.  Maybe a travis issue?
