Instance creation fails with NovaException: Error mounting with libguestfs

The issue was discovered with the following steps:

1. Deploy Fuel 4.0.
2. Clone tempest (Havana stable branch) to Controller node.
3. Configure tempest.
4. Run
nosetests -sv tempest/api/compute/servers/test_create_server.py

This script creates instances with code:
cls.create_server(name=cls.name,
                                     meta=cls.meta,
                                     accessIPv4=cls.accessIPv4,
                                     accessIPv6=cls.accessIPv6,
                                     personality=personality,
                                     disk_config=cls.disk_config)

This code sends request with body:
{"server": {"name": "server82800933", "imageRef": "2c97f855-a19d-4c08-8f6d-7b74df66befe", "flavorRef": 1, "OS-DCF:diskConfig": "AUTO", "accessIPv4": "1.1.1.1", "accessIPv6": "0000:0000:0000:0000:0000:babe:220.12.22.2", "metadata": {"hello": "world"}, "personality": [{"path": "/test.txt", "contents": "VGhpcyBpcyBhIHRlc3QgZmlsZS4="}]}}

Result: instance in ERROR status.
/var/log/nova-all.log contains:

<0>Mar 5 15:29:07 node-13 ¿<182>nova-nova.virt.libvirt.driver INFO: Creating image
<0>Mar 5 15:29:08 node-13 ¿<182>nova-nova.virt.libvirt.driver INFO: Injecting metadata into image 2c97f855-a19d-4c08-8f6d-7b74df66befe
<0>Mar 5 15:29:08 node-13 ¿<182>nova-nova.virt.libvirt.driver INFO: Injecting files into image 2c97f855-a19d-4c08-8f6d-7b74df66befe
<0>Mar 5 15:29:08 node-13 ¿<179>nova-nova.virt.libvirt.driver ERROR: Error injecting data into image 2c97f855-a19d-4c08-8f6d-7b74df66befe (Error mounting /var/lib/nova/instances/d5069cc1-f144-4493-8ee6-9abe32c6dd44/disk with libguestfs (command failed: LC_ALL=C '/usr/libexec/qemu-kvm' -nographic -help
errno: File exists

If qemu is located on a non-standard path, try setting the LIBGUESTFS_QEMU
environment variable. There may also be errors printed above.))
<0>Mar 5 15:29:08 node-13 ¿<179>nova-nova.compute.manager ERROR: Instance failed to spawn
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 1417, in _spawn
    block_device_info)
  File "/usr/lib/python2.6/site-packages/nova/virt/libvirt/driver.py", line 2067, in spawn
    admin_pass=admin_password)
  File "/usr/lib/python2.6/site-packages/nova/virt/libvirt/driver.py", line 2500, in _create_image
    instance=instance)
  File "/usr/lib/python2.6/site-packages/nova/virt/libvirt/driver.py", line 2494, in _create_image
    mandatory=('files',))
  File "/usr/lib/python2.6/site-packages/nova/virt/disk/api.py", line 325, in inject_data
    fs.setup()
  File "/usr/lib/python2.6/site-packages/nova/virt/disk/vfs/guestfs.py", line 129, in setup
    {'imgfile': self.imgfile, 'e': e})
NovaException: Error mounting /var/lib/nova/instances/d5069cc1-f144-4493-8ee6-9abe32c6dd44/disk with libguestfs (command failed: LC_ALL=C '/usr/libexec/qemu-kvm' -nographic -help
errno: File exists

If qemu is located on a non-standard path, try setting the LIBGUESTFS_QEMU
environment variable. There may also be errors printed above.)

The following steps helped to fix this issue:

1. qemu-kvm is located in /usr/bin folder but libguestfs expect it in /usr/libexec/ folder.
So, on each Compute node do this :
ln -s /usr/bin/qemu-kvm /usr/libexec/qemu-kvm

2. Apply fix for bug https://bugzilla.redhat.com/show_bug.cgi?id=894241#c11 :
On each Compute node, add these to the supermin hostfiles (/usr/lib64/guestfs/supermin.d/hostfiles):
/usr/share/augeas/lenses/dist/quote.aug
/usr/share/augeas/lenses/dist/simplevars.aug