Fix kvm support in Ubuntu

Fix kvm support in Ubuntu

In Ubuntu, there is no qemu-kvm, only kvm executable.
check qemu-kvm, and kvm executable file.

qemu options has changed.
problem:
  [  129s] qemu-system-x86_64: -drive file=/home/hglee/GBS-ROOT/t65std/local/BUILD-ROOTS/scratch.armv7l.0.img,format=raw,if=none,id=disk,serial=1,cache=unsafe: Block format 'raw' does not support the option 'serial'

fix serial option

ref:
- https://github.com/openSUSE/obs-build/commit/2514958e1d6af6c10515eea995ae03b01a9b762c

Change-Id: I32c51a923b25cb25f6ec1551a3b73e66f3f782e6
Signed-off-by: Hyunggi Lee <hyunggi.lee@samsung.com>