Bug 1270182 - Travis: Add missing `--disable-pip-version-check`s
Bug 1270182 - Travis: Add missing `--disable-pip-version-check`s

Makes all `pip install` invocations consistent.

tojon/treeherder,kapy2010/treeherder,glenn124f/treeherder,akhileshpillai/treeherder,edmorley/treeherder,kapy2010/treeherder,KWierso/treeherder,KWierso/treeherder,glenn124f/treeherder,tojon/treeherder,akhileshpillai/treeherder,kapy2010/treeherder,tojon/treeherder,tojonmz/treeherder,glenn124f/treeherder,KWierso/treeherder,akhileshpillai/treeherder,kapy2010/treeherder,KWierso/treeherder,tojonmz/treeherder,glenn124f/treeherder,akhileshpillai/treeherder,kapy2010/treeherder,tojonmz/treeherder,edmorley/treeherder,tojonmz/treeherder,tojonmz/treeherder,glenn124f/treeherder,glenn124f/treeherder,akhileshpillai/treeherder,edmorley/treeherder,edmorley/treeherder,tojon/treeherder,akhileshpillai/treeherder,tojonmz/treeherder