qemu.tests.qmp_command: Pylint and Eclipse fixes

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
qemu.tests.qmp_command: Repair function call of has_option()

qemu_command has to be passed to qemu_has_option() function.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
qemu.tests.qmp_command: Add quotes around outputs

Quite often the only difference between HMP and QMP monitor
output is missing or additional space. Add '' around outputs
to help finding those bugs.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>