Update pytest to 3.5.0 (#3365)
Update pytest to 3.5.0 (#3365)


edmorley/treeherder,KWierso/treeherder,edmorley/treeherder,KWierso/treeherder,KWierso/treeherder,edmorley/treeherder,KWierso/treeherder,edmorley/treeherder