v2v: docs: Change examples so -i input comes before -o options.

Make the input/output ordering of command line arguments clearer by
changing:

 virt-v2v -i disk -o local -os /var/tmp disk.img

to:

 virt-v2v -i disk disk.img -o local -os /var/tmp
v2v: Add -o qemu output mode and --qemu-boot flag.

This lets you write a shell script that runs the guest under qemu.
Specifying the --qemu-boot flag also boots the guest after conversion.
v2v: Disable valgrind tests that are confused by -o rhev forking.

This updates commit 0dfa96c043cee4ce82c0a45c3ad09b0a61798b79.
valgrind: Add suppression for another libvirt/selinux leak.
v2v: -o rhev/vdsm: Remove the test that the storage domain is writable.

For '-o rhev' this is likely to fail (although for obscure reasons it
*doesn't* fail on a real RHEV server, I don't quite understand why).
The reason is because virt-v2v may be running as root, and with root
squashing we don't have permissions to write into the storage domain
directory.

For '-o vdsm', VDSM is supposed to make sure we are running as the
correct user, so there's no reason to doubt things will work.
v2v: -o rhev: Use a random name when testing UID:GID mapping.

Using a fixed name is risky if there are multiple parallel virt-v2v
processes running.
v2v: -o rhev: On failure path, use forking wrapper to clean up images dir.

Otherwise you get lots of errors like:

rm: cannot remove ‘/var/tmp/mm/42f5e571-21af-44bd-8164-3ebe6bbc9f5a/images/7b28b0e6-79ce-4d78-a6cb-769760a3d373/31e2b06b-85cb-46ed-aac3-8bcef93dc704.meta’: Permission denied
rm: cannot remove ‘/var/tmp/mm/42f5e571-21af-44bd-8164-3ebe6bbc9f5a/images/7b28b0e6-79ce-4d78-a6cb-769760a3d373/31e2b06b-85cb-46ed-aac3-8bcef93dc704’: Permission denied

because the code is running as root.
v2v: -o rhev: chmod the image so we will definitely be able to write to it.

NFS sucks.
syntax-check: fix prohibit_assert_without_use check

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
syntax-check: fix prohibit_c_ctype_without_use check

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
syntax-check: fix prohibit_dirent_without_use check

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
syntax-check: fix prohibit_getopt_without_use check

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>