netcdf links with libsz.dylib without declaring dependency on szip

[ryandesign (Ryan Carsten Schmidt)]

libnetcdf.dylib links with libsz.dylib though the netcdf port does not declare a library dependency on the szip port.

$ otool -L /opt/local/lib/libnetcdf.dylib
/opt/local/lib/libnetcdf.dylib:
	/opt/local/lib/libnetcdf.7.dylib (compatibility version 10.0.0, current version 10.0.0)
	/opt/local/lib/libhdf5_hl.7.dylib (compatibility version 8.0.0, current version 8.3.0)
	/opt/local/lib/libhdf5.7.dylib (compatibility version 8.0.0, current version 8.3.0)
	/opt/local/lib/libsz.2.dylib (compatibility version 3.0.0, current version 3.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.11)
	/opt/local/lib/libcurl.4.dylib (compatibility version 7.0.0, current version 7.0.0)
	/opt/local/lib/libidn.11.dylib (compatibility version 18.0.0, current version 18.8.0)
	/opt/local/lib/libintl.8.dylib (compatibility version 10.0.0, current version 10.1.0)
	/opt/local/lib/libiconv.2.dylib (compatibility version 8.0.0, current version 8.1.0)
	/opt/local/lib/libssl.1.0.0.dylib (compatibility version 1.0.0, current version 1.0.0)
	/opt/local/lib/libcrypto.1.0.0.dylib (compatibility version 1.0.0, current version 1.0.0)
	/opt/local/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.7)

This is probably a result of r93151.

[tenomoto (Takeshi Enomoto)]

Committed in r94814.