api/report-commit should authenticate with a slave name and password

api/report-commit should authenticate with a slave name and password
https://bugs.webkit.org/show_bug.cgi?id=140308

Reviewed by Benjamin Poulain.

Use a slave name and a password to authenticate new commit reports.

* public/api/report-commits.php:
(main):
* public/include/json-header.php:
(verify_slave): Renamed and repurposed from verify_builder in report-commits.php. Now authenticates with
a slave name and a password instead of a builder name and a password.
* tests/api-report-commits.js: Updated tests.
* tools/pull-svn.py:
(main): Renamed variables.
(submit_commits): Submits slaveName and slavePassword instead of builderName and builderPassword.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@178200 268f45cc-cd09-0410-ab3c-d52691b4dbfc