Small cleanup for zlib decompression.
Small cleanup for zlib decompression.

ahaberlie/MetPy,ShawnMurd/MetPy,ahill818/MetPy,dopplershift/MetPy,Unidata/MetPy,deeplycloudy/MetPy,jrleeman/MetPy,Unidata/MetPy,dopplershift/MetPy,jrleeman/MetPy,ahaberlie/MetPy