Usually, we have this 'if() goto cleanup;' pattern in our new
code. It is going to be useful here too. Thing is, there was a
memleak. If there has been an error in
virNetServerProgramSendStreamError() or
virNetServerProgramSendStreamData() created message was never
freed.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>