packages/python/build: update comments for correctness
packages/python/build: update comments for correctness

CPython 3.6.6 actually brings pip 10.0.1.

mesosphere-mergebot/dcos,kensipe/dcos,mesosphere-mergebot/dcos,surdy/dcos,dcos/dcos,mesosphere-mergebot/mergebot-test-dcos,mesosphere-mergebot/dcos,kensipe/dcos,GoelDeepak/dcos,GoelDeepak/dcos,kensipe/dcos,GoelDeepak/dcos,GoelDeepak/dcos,dcos/dcos,kensipe/dcos,surdy/dcos,dcos/dcos,mesosphere-mergebot/mergebot-test-dcos,mesosphere-mergebot/mergebot-test-dcos,mesosphere-mergebot/dcos,surdy/dcos,mesosphere-mergebot/mergebot-test-dcos,surdy/dcos,dcos/dcos,dcos/dcos