(py3) Encode subprocess input as bytes.
In python2, the subprocess interface doesn't care if you pass it bytes
or unicode, but in python3 you have to be explicit. This should fix
`fpaste -i -o` usage under python3 (F23).
Signed-off-by: Ralph Bean <rbean@redhat.com>
Signed-off-by: Ankur Sinha (Ankur Sinha Gmail) <sanjay.ankur@gmail.com>