Remove pip version specifier

We don't actually require pip 1.4, and saying that we do
breaks package installation in a lot of cases. Remove the
version specifier from our requirements list.

Fixes-bug: #1296310
Change-Id: I69c67c4c8cba7076e33292eaab9070ba51b4dff3
Use unicode_literals import instead of u'unicode' notation.

Change-Id: I94ff7e2517c714b9f576f9f9f615537502fcbf41
Closes-Bug: #1276139