docs(jenkins): Update Jenkins documentation
docs(jenkins): Update Jenkins documentation

Current versions of the karma-junit-reporter and the given sample configuration
store the report below directories named after the browsers the tests were run
in, which must be reflected in the Jenkins configuration.

Dignifiedquire/karma,karma-runner/karma,wesleycho/karma,ernsheong/karma,johnjbarton/karma,kahwee/karma,karma-runner/karma,shirish87/karma,david-garcia-nete/karma,pedrotcaraujo/karma,maksimr/karma,Dignifiedquire/karma,johnjbarton/karma,Dignifiedquire/karma,ernsheong/karma,buley/karma,buley/karma,skycocker/karma,mprobst/karma,shirish87/karma,panrafal/karma,marthinus-engelbrecht/karma,johnjbarton/karma,SamuelMarks/karma,david-garcia-nete/karma,wesleycho/karma,johnjbarton/karma,karma-runner/karma,kahwee/karma,shirish87/karma,maksimr/karma,SamuelMarks/karma,panrafal/karma,skycocker/karma,maksimr/karma,mprobst/karma,skycocker/karma,SamuelMarks/karma,david-garcia-nete/karma,skycocker/karma,buley/karma,marthinus-engelbrecht/karma,panrafal/karma,kahwee/karma,pedrotcaraujo/karma,karma-runner/karma,kahwee/karma,pedrotcaraujo/karma,ernsheong/karma,wesleycho/karma,mprobst/karma,marthinus-engelbrecht/karma,buley/karma,wesleycho/karma,Dignifiedquire/karma,marthinus-engelbrecht/karma,pedrotcaraujo/karma