(eloquent) Add operator!= to Duration

[ivanpauno]

Backports #1236.

This is an addition, not a bug fix.
It makes sense to me to backport this for consistency. It's weird to have all comparison operators except !=.

[mjcarroll]

LGTM, but I'm having trouble determining what caused the build to go red.

[ivanpauno]

06:36:27 WARNING: The converted file for the input file '/home/jenkins-agent/workspace/Epr__rclcpp__ubuntu_bionic_amd64/ws/test_results/rclcpp/Testing/20200814-1333/Test.xml' doesnt match the JUnit format.
06:36:27 WARNING: At line 2 of file:/home/jenkins-agent/workspace/Epr__rclcpp__ubuntu_bionic_amd64/generatedJUnitFiles/78066d8c-0342-4b57-8755-dce13d49c188/GoogleTest/TEST-7264dd97-ae13-4794-8c46-89af4792e5f2.xml:Premature end of file.
06:36:27 WARNING: Technical validation:Premature end of file.
06:36:27 ERROR: Premature end of file.
06:36:27 ERROR: Premature end of file.
06:36:27 ERROR: Step ‘Publish xUnit test result report’ failed: The converted file for the result file '/home/jenkins-agent/workspace/Epr__rclcpp__ubuntu_bionic_amd64/ws/test_results/rclcpp/Testing/20200814-1333/Test.xml' (during conversion process for the metric 'GoogleTest') is not valid. The report file has been skipped.

😮

[dirk-thomas]

@ros-pull-request-builder retest this please (using custom job config from ros-infrastructure/ros_buildfarm#828)

[audrow]

LGTM, pending Docs test and the build passing.

[audrow]

(Oops, meant to review one of the other backports.)

[ivanpauno]

@ros-pull-request-builder retest this please

[jacobperron]

@ros-pull-request-builder retest this please (using custom job config from ros-infrastructure/ros_buildfarm#831)

[ivanpauno]

@ros-pull-request-builder retest this please

[ivanpauno]

Closing as eloquent is EOL