java: hashCode must supplement equals

Author: barancev

java/client/src/org/openqa/selenium/mobile/NetworkConnection.java

@@ -99,6 +99,11 @@ public boolean equals(Object type) {
       return type instanceof ConnectionType && this.mask == ((ConnectionType) type).mask;
     }
 
+    @Override
+    public int hashCode() {
+      return mask;
+    }
+
     @Override
     public String toString() {
       return Integer.toString(mask);