pwclient get: fix for handling messages encoded in UTF-8

pwclient get: fix for handling messages encoded in UTF-8

Trying `pwclient get` with a message containing UTF-8 characters you
would get the following error.

    $ python -v pwclient get ID
    [...]
    # trying /usr/lib/python2.5/encodings/ascii.so
    # trying /usr/lib/python2.5/encodings/asciimodule.so
    # trying /usr/lib/python2.5/encodings/ascii.py
    # /usr/lib/python2.5/encodings/ascii.pyc matches /usr/lib/python2.5/encodings/ascii.py
    import encodings.ascii # precompiled from /usr/lib/python2.5/encodings/ascii.pyc
    Failed to write to subject.patch
    [...]

You can reproduce it with

    $ pwclient get http://patchwork.openembedded.org/patch/1440/

and the fix is the same as in 4fc6a16910e595401e919abde28cca436193e0dd
by Mauro Carvalho Chehab.

Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>