Remove log-level argument from spawner script

[bijoua29]

This change is to partially revert the changes in PR 972 which added a log-level argument to the spawner to control the output of the spawner node using the logging level. It turns out that using standard ros-args conventions for the 'ros2 run' command to set the logging level was sufficient.

So instead of adding a new way to set the logging level of the spawner with:

ros2 run controller_manager spawner --log-level WARN

the old way using ros-args was sufficient:

ros2 run controller_manager spawner --ros-args --log-level WARN

I have tested that this works.

[codecov-commenter]

Codecov Report

Merging #1013 (4b6bbac) into master (925f5f3) will decrease coverage by 1.93%.
The diff coverage is 35.61%.

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@@            Coverage Diff             @@
##           master    #1013      +/-   ##
==========================================
- Coverage   34.61%   32.69%   -1.93%     
==========================================
  Files          52       91      +39     
  Lines        2981     9551    +6570     
  Branches     1855     6432    +4577     
==========================================
+ Hits         1032     3123    +2091     
- Misses        310      704     +394     
- Partials     1639     5724    +4085     

Flag	Coverage Δ
unittests	32.69% <35.61%> (-1.93%)	⬇️

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

Impacted Files	Coverage Δ
controller_manager/src/controller_manager.cpp	38.27% <ø> (-1.44%)	⬇️
controller_manager/src/ros2_control_node.cpp	0.00% <0.00%> (ø)
..._interface/include/hardware_interface/actuator.hpp	100.00% <ø> (ø)
...re_interface/include/hardware_interface/sensor.hpp	100.00% <ø> (ø)
...re_interface/include/hardware_interface/system.hpp	100.00% <ø> (ø)
hardware_interface/src/resource_manager.cpp	49.91% <ø> (-3.72%)	⬇️
hardware_interface/src/sensor.cpp	50.52% <ø> (ø)
hardware_interface/src/system.cpp	55.45% <ø> (ø)
...rface/test/mock_components/test_generic_system.cpp	9.14% <ø> (ø)
...dware_interface/test/test_component_interfaces.cpp	32.44% <ø> (+4.25%)	⬆️
... and 68 more

... and 19 files with indirect coverage changes

[christophfroehlich]

this looks reasonable!