trac_ik fails on melodic

edit

Hello list,

After loading a simple urdf in the parameter server using the following launch file:

<launch>
  <param name="robot_description"
    command="xacro '$(find tf_if_test)/urdf/boot.xacro' " />

  <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher">
    <param name="use_gui" value="true"/>
  </node>

  <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher"/>
  <node name="rviz" pkg="rviz" type="rviz" args="-d $(find tf_if_test/launch/boot.rviz"/>
</launch>

This works fine, but if I try to use trac_ik_python, but it fails with the following error:

terminate called after throwing an instance of 'ros::TimeNotInitializedException'
  what():  Cannot use ros::Time::now() before the first NodeHandle has been created or ros::start() has been called.  If this is a standalone app or test that just uses ros::Time and does not communicate over ROS, you may also call ros::Time::init()
Aborted (core dumped)

The code:

#!/usr/bin/env python                                                                                                       
import rospy
from trac_ik_python.trac_ik import IK

rospy.init_node('tester', anonymous=True)
ik_solver = IK("l1",               "l3")
print 'done'

I thought that init_node did the ros::start() here. Am I doing something wrong?

EDIT: Or is it a problem that there are only 2DOF in this robot?

2nd EDIT: I tried the patch by adding the ros::Timer::init() in the swig-file. That works. Then I removed that patched version of trac_ik completely and reverted to the official one. Now the problem does NOT return, It is really reverted, I also rebooted the machine. Weird....

Thanks in advance, Sietse