Fix small indenting error.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Avoid leaking syslog connections with every log write

We need to cache the result of Syslog.openlog and only close it
if we want to change service name.

Fixes xen-org/squeezed#10

Signed-off-by: David Scott <dave.scott@eu.citrix.com>