conf: Initialize _virNetworkObj::dnsmasqPid to -1 in virNetworkObjNew()

Throughout all of our network driver code we assume that
dnsmasqPid of value -1 means the network has no dnsmasq process
running. There are plenty of calls to:

  virNetworkObjSetDnsmasqPid(obj, -1);

or:

  pid_t dnsmasqPid = virNetworkObjGetDnsmasqPid(obj);
  if (dnsmasqPid > 0) ...;

Now, a virNetworkObj is created via virNetworkObjNew() which
might as well set this de-facto default value.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/conf/virnetworkobj.c

@@ -117,6 +117,7 @@ virNetworkObjNew(void)
     ignore_value(virBitmapSetBit(obj->classIdMap, 2));
 
     obj->ports = virHashNew(virNetworkObjPortFree);
+    obj->dnsmasqPid = (pid_t)-1;
 
     virObjectLock(obj);