Remove python 2.7 support

Remove python 2.7 support

As per the deprecation notice python 2.7 is not long supported.
This causing job failures since the dependencies install
are not maintained.

DEPRECATION: Python 2.7 reached the end of its life on January 1st,
2020. Please upgrade your Python as Python 2.7 is no longer
maintained. pip 21.0 will drop support for Python 2.7 in January
2021. More details about Python 2 support in pip can be found at
https://pip.pypa.io/en/latest/development/release-process/#python-2-support
pip 21.0 will remove support for this functionality.

Issue: RELENG-3375
Change-Id: I48cc4b91b9916918d222794534db5ade9b58dda0
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>