syslog: supply the facility every time
syslog: supply the facility every time

Supplying the facility during `openlog` wasn't working: all logs
were being sent as `USER` rather than `DAEMON`.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

xapi-project/message-switch,xapi-project/message-switch,xapi-project/message-switch