(2.12) QMP: test supported_commands
(2.12) QMP: test supported_commands

Add test for supported_commands.

Signed-off-by: Apollon Oikonomopoulos <ed81ed0a45ccd5c8869bda52e38353a6299ee39e@gmail.com>
Signed-off-by: Thomas Thrainer <98bdeac947eb8ca18146e9ce7f092788ec242cd1@google.com>
Reviewed-by: Thomas Thrainer <98bdeac947eb8ca18146e9ce7f092788ec242cd1@google.com>

apyrgio/snf-ganeti,apyrgio/snf-ganeti