Fix next controller update cycle time clock

[saikishor]

Fixes #1126

[christophfroehlich]

I tested this with the gazebo_ros2_control_demos, they are working now again.

[fmauch]

Not the prettiest thing in the world, but definitely works. Tested against ros2_control_demos and ur_robot_driver.

[codecov]

Codecov Report

Merging #1127 (4bc0f68) into master (dd27066) will increase coverage by 0.01%.
Report is 1 commits behind head on master.
The diff coverage is 49.09%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1127      +/-   ##
==========================================
+ Coverage   31.55%   31.57%   +0.01%     
==========================================
  Files          94       94              
  Lines       10730    10736       +6     
  Branches     7345     7347       +2     
==========================================
+ Hits         3386     3390       +4     
  Misses        804      804              
- Partials     6540     6542       +2     

Flag	Coverage Δ
unittests	31.57% <49.09%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
controller_manager/test/test_spawner_unspawner.cpp	28.57% <100.00%> (ø)
...ontroller_manager/test/test_controller_manager.cpp	27.20% <94.44%> (ø)
...t_controllers_chaining_with_controller_manager.cpp	31.15% <0.00%> (ø)
...er_manager/test/controller_manager_test_common.hpp	50.66% <50.00%> (-0.69%)	⬇️
controller_manager/src/controller_manager.cpp	38.38% <40.00%> (+0.17%)	⬆️
...est_controller_manager_hardware_error_handling.cpp	27.42% <0.00%> (ø)

[bmagyar]

thanks for the quick fix!