[travis] nosetests should not be run with python run.py -t

[karlcow]

Following the discussion in #2518 (comment)

At any rate, you're right, of course -- it's not that nosetests kicks run.py directly... it's that in Travis we always execute run.py -t before we run nosetests (or, rather, all the test scripts). (At least digging into all this, I learned a bunch of stuff about our configuration! (-; )

This should not happen. It's a "bug".

We should start python run.py -t after nosetests has run.

[karlcow]

Relevant section

webcompat.com/.travis.yml

Lines 41 to 62 in 42781cc

	install:
	- travis_retry npm install
	- travis_retry npm run pip
	- travis_retry npm run config
	- which firefox
	- java -version
	- firefox --version
	# lint python
	- pep8 --ignore=E402 webcompat/ tests/ config/secrets.py.example
	- python run.py -t &
	before_script:
	- sleep 5
	# lint JS in default eslint task
	- npm run lint
	- npm run build
	# now run the tests!
	script:
	- nosetests
	- sleep 5
	- npm run test:js -- --reporters="runner" --firefoxBinary=`which firefox`