fixed the undefined behavior for tripple buffer initialization

source/RobotAPI/libraries/RobotAPINJointControllers/DMPController/NJointTaskSpaceImpedanceDMPController.cpp

@@ -551,6 +551,11 @@ namespace armarx
             usleep(100);
         }
 
+        while (!interfaceData.updateReadBuffer())
+        {
+            usleep(100);
+        }
+
         Eigen::Matrix4f pose = interfaceData.getUpToDateReadBuffer().currentTcpPose;
         dmpCtrl->prepareExecution(dmpCtrl->eigen4f2vec(pose), goals);