Replace 'hasTox' label with 'contintLabsSlave'

Updates jobs:

analytics-limn-mobile-data-tox-flake8
analytics-wikimetrics-tox-flake8
integration-jjb-config-diff
integration-jjb-config-test
mw-tools-release-tox-flake8
mw-tools-release-tox-py27
mw-tools-releng-tox-doc
mw-tools-releng-tox-doc-publish
mw-tools-scap-tox-doc
mw-tools-scap-tox-doc-publish
mw-tools-scap-tox-flake8
mw-tools-scap-tox-py27
pywikibot-core-tox-flake8

Change-Id: I506540932b03dcf681f2fecc82044352afb81eeb