group_replication_group_name anymore when storing usage data

Removed the reading of the group_replication_group_name system variable
by the option_tracker component.
Updated the doxygen about this.
Removed setting the variable to some weird value during tests.
Re-recorded the affected test result.
Reading the row updates now ignores the cluster ID too.

Change-Id: I76eba54d52931c3ba7b7a892bac7ab400eb1eb8d