remove 'return'

looks unnecessary 

Author: Yoshihiro Shimizu <shimizu@amoad.com>

Closes #4268 from y-shimizu/remove-return and squashes the following commits:

12be0e9 [Yoshihiro Shimizu] remove 'return'

mllib/src/main/scala/org/apache/spark/mllib/linalg/Vectors.scala

@@ -78,7 +78,7 @@ sealed trait Vector extends Serializable {
         result = 31 * result + (bits ^ (bits >>> 32)).toInt
       }
     }
-    return result
+    result
   }
 
   /**