openvz_conf.c: don't use undefined local, "net"

* src/openvz_conf.c (openvzReadNetworkConf): Initialize "net".
Otherwise, upon openvzRead... failure, we would "goto error;"
where an uninitialized "net" could be dereferenced.

src/openvz_conf.c

@@ -183,7 +183,7 @@ openvzReadNetworkConf(virConnectPtr conn,
                       virDomainDefPtr def,
                       int veid) {
     int ret;
-    virDomainNetDefPtr net;
+    virDomainNetDefPtr net = NULL;
     char temp[4096];
     char *token, *saveptr = NULL;