virt-host-validate-bhyve.c: Reintroduce @ret to virHostValidateBhyve()

This partially reverts fe65e9c8.

In the referenced commit I removed @ret from
virHostValidateBhyve() thinking it wasn't used when in fact it is
- it's usage is hidden under MODULE_STATUS_WARN(). Reintroduce
the variable back.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

tools/virt-host-validate-bhyve.c

@@ -47,6 +47,7 @@
 
 int virHostValidateBhyve(void)
 {
+    int ret = 0;
     int fileid = 0;
     struct kld_file_stat stat;
     bool vmm_loaded = false, if_tap_loaded = false;
@@ -72,5 +73,5 @@ int virHostValidateBhyve(void)
     MODULE_STATUS_WARN(if_bridge, "bridged networking will not work");
     MODULE_STATUS_WARN(nmdm, "nmdm console will not work");
 
-    return 0;
+    return ret;
 }