Change "dict.has_key(key)" to "key in dict"

This is necessary for Python 3 compatibility.

Done using:

  $ py=$( (g grep -l -E '^#!.*python';find -name '*.py' -printf '%P\n';) | \
    sort -u | grep -v README.sh4)
  $ futurize -w -f lib2to3.fixes.fix_has_key $py
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180608122952.2009-5-ehabkost@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>