qemuMonitorJSONMakeCommandInternal does the full command construction if
you pass in what would become the value of the 'arguments' key. Refactor
the open-coded implementation to use the helper and use modern cleanup
helpers at the same time.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>