libvirt: add a configuration file named drivers.cfg

Currently, the special configurations for specific driver is rewrite
in setting params of libvirt_vm.VM. This patch move this work to the
configuration file parsing.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
libvirt_vm: recreate serial in lxc.wait_for_login()

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
utils_misc: Fix get_image_info fail to get format

For qemu-img-1.5.3, We get following message when running:
> qemu-img info /var/lib/virt_test/images/jeos-19-64.qcow2
image: /var/lib/virt_test/images/jeos-19-64.qcow2
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 761M
cluster_size: 65536
Format specific information:
    compat: 0.10

The `Format specific information:` line which containing a
`Format` will flush the saved file format. Now we use a more
specific line to check file format.

Signed-off-by: Hao Liu <hliu@redhat.com>
shared.cfg: Small fix for Win2012.cfg

Signed-off-by: Shuping Cui <scui@redhat.com>
Merge pull request #1752 from spcui/format_disk_fix

shared.cfg: Small fix for Win2012.cfg
Merge pull request #1740 from yangdongsheng/lxc

libvirt: add a configuration file named drivers.cfg
env_process: mv creating of vm into libvirt specific block.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Merge pull request #1753 from yangdongsheng/lxc_fix

env_process: mv creating of vm into libvirt specific block.
env_process: Do not getattr of vm if vm is None.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Merge pull request #1754 from yangdongsheng/lxc_fix

env_process: Do not getattr of vm if vm is None.
Merge pull request #1744 from Hao-Liu/fix_qemu_img_info

utils_misc: Fix get_image_info fail to get format
virttest.utils_misc: support killing a process with pattern

Signed-off-by: Alex Jia <chuanchang.jia@gmail.com>