Description of problem:
qed format is support in libvirt. But in virt-convert, it is not support now.
If you convert a vmx format to qed disk format, error message would popup:
"virt-convert: error: Unknown output disk format "qed""

check the related code, ./site-packages/virtconv/diskcfg.py, there is no qed format supported in it.
disk_format_names = {
    "none": DISK_FORMAT_NONE,
    "raw": DISK_FORMAT_RAW,
    "vmdk": DISK_FORMAT_VMDK,
    "vdisk": DISK_FORMAT_VDISK,
    "qcow": DISK_FORMAT_QCOW,
    "qcow2": DISK_FORMAT_QCOW2,
    "cow": DISK_FORMAT_COW,
}


Version-Release number of selected component (if applicable):
python-virtinst-0.600.0-8.el6.noarch

How reproducible:
100%

Steps to Reproduce:
#virt-convert -i vmx -o virt-image -D qed /tmp/vmware/*.vmx

Check if the conversion successful.

Actual results:
Failed. Error message pop up "virt-convert: error: Unknown output disk format "qed""

Expect result:
Support qed format in virt-convert