qemu-img: drop -e and -6 options from the 'create' & 'convert' commands

qemu-img: drop -e and -6 options from the 'create' & 'convert' commands

The '-e' and '-6' options to the 'create' & 'convert' commands were
"deprecated" in favour of the more generic '-o' option many years ago:

  commit eec77d9e712bd4157a4e1c0b5a9249d168add738
  Author: Jes Sorensen <Jes.Sorensen@redhat.com>
  Date:   Tue Dec 7 17:44:34 2010 +0100

    qemu-img: Deprecate obsolete -6 and -e options

Except this was never actually a deprecation, which would imply giving
the user a warning while the functionality continues to work for a
number of releases before eventual removal. Instead the options were
immediately turned into an error + exit. Given that the functionality
is already broken, there's no point in keeping these psuedo-deprecation
messages around any longer.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>