Don't require encryption password for 'qemu-img info' command

Don't require encryption password for 'qemu-img info' command

The encryption password is only required if I/O is going to be
performed on a disk image. The 'qemu-img info' command merely
reports metadata, so it should not ask for a decryption password

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit f0536bb848ad6eb2709a7dc675f261bd160c751b)

Conflicts:

	qemu-img.c

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>