Use syslog from xcp-idl for now
Use syslog from xcp-idl for now

Core.Unix.Syslog got renamed to Syslog and made part of core.syslog.
However we cannot link that as it conflicts with the Syslog module in
xcp-idl.

For now switch to using the syslog module from xcp-idl instead.

Signed-off-by: Edwin Török <c8d178016cbaf8a6ef23c2cbc9db96123c48b7dc@citrix.com>

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