Fix error thrown when disconnecting blocks that have never been dragged.

core/block_svg.js

@@ -828,6 +828,8 @@ Blockly.BlockSvg.prototype.onMouseMove_ = function(e) {
       if (this.parentBlock_) {
         // Push this block to the very top of the stack.
         this.unplug();
+        var group = this.getSvgRoot();
+        group.translate_ = 'translate(' + newXY.x + ',' + newXY.y + ')';
         this.disconnectUiEffect();
       }
       this.setDragging_(true);

core/connection.js

@@ -64,6 +64,7 @@ Blockly.Connection.REASON_DIFFERENT_WORKSPACES = 5;
  * Connect two connections together.
  * @param {!Blockly.Connection} parentConnection Connection on superior block.
  * @param {!Blockly.Connection} childConnection Connection on inferior block.
+ * @private
  */
 Blockly.Connection.connect_ = function(parentConnection, childConnection) {
   var parentBlock = parentConnection.getSourceBlock();