This patch benefits from the better error message when key is missing
in config params. Instead of custom handling of missing param it
uses params[] directly.

I modified those params, where I was 100% certain that they are
required and doesn't have default value:
 * val = params.get(..) followed by if not val: raise...
 * int(params.get(...))
 * params.get(...).split()
 * commands which require string (eg. session.cmd(params.get(...)))

I didn't test all the tests before and after in order to verify
possible typos but I used pylint before and after, watching for
new errors (code rate before and after).
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

A frequent request we've got from users is that the name
'kvm' makes assumptions that are not true for a lot of
the use cases of the test suite. Then let's rename
the subtest 'kvm' to 'qemu', making it more accurate.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

All disk images, kernels and any file that will be
stored in the data dir should use the new data dir
reference.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

Currently, the commit test just use qemu_img, which
install in the system as default, to make the backup
file, and use the qemu_img_binary which get the path
from env file. Thus may bring some bugs.

For example, if just use the qemu source code and
don't make install to the system(that means the
system haven't installed a qemu to /usr/local/bin
or other system bin path, and autotest just test
the qemu using the git tree), the test will not
find the qemu_img_binary to create the backing_file.

and another problem is the binary used to backup and
commit may be different version, this may cause a bug.

To solve the problem, make the same binary to backup
and commit.
Signed-off-by: NMike Qiu <qiudayu@linux.vnet.ibm.com>

Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>