fix ANDROID-49: VirtualNetworkConfig.equals is wrong

java/src/com/zerotier/sdk/VirtualNetworkConfig.java

@@ -154,7 +154,7 @@ public final class VirtualNetworkConfig implements Comparable<VirtualNetworkConf
         }
 
         boolean dnsEquals = false;
-        if (this.dns == null || cfg.dns == null) {
+        if (this.dns == null && cfg.dns == null) {
             dnsEquals = true;
         } else if (this.dns != null) {
             dnsEquals = this.dns.equals(cfg.dns);