fix bytes/str mess in packfloats1 and packfloats2
fix bytes/str mess in packfloats1 and packfloats2

They should return bytes consistently, as pyvisa does not handle
translation from bytes to str for you.

git-svn-id: 9ab2475816adfb8420036182e3900ffc754382bd@383 516c0664-e049-0410-bc6e-8f9a6051a51d

MatthieuDartiailh/pyvisa,pyvisa/pyvisa,hgrecco/pyvisa,rubund/debian-pyvisa