Not uninstalling paramiko at /usr/lib/python2.7/dist-packages, outside environment /usr

I am trying to upgrade paramiko on Ubuntu 16.04 4.4.0 with pip 8.1.1:

pip install -U paramiko
...
Installing collected packages: idna, setuptools, enum34, pycparser, cffi, cryptography, paramiko
  Found existing installation: idna 2.0
    Not uninstalling idna at /usr/lib/python2.7/dist-packages, outside environment /usr
  Found existing installation: setuptools 20.7.0
    Not uninstalling setuptools at /usr/lib/python2.7/dist-packages, outside environment /usr
  Found existing installation: enum34 1.1.2
    Not uninstalling enum34 at /usr/lib/python2.7/dist-packages, outside environment /usr
  Found existing installation: cryptography 1.2.3
    Not uninstalling cryptography at /usr/lib/python2.7/dist-packages, outside environment /usr
  Found existing installation: paramiko 1.16.0
    Not uninstalling paramiko at /usr/lib/python2.7/dist-packages, outside environment /usr

Is this a bug or am I missing something?

Full log

Same issue if I try to upgrade pip itself.

I guess your problem is related to the problem discussed here.

Try to delete paramiko package using apt-get first: apt-get remove python-paramiko.

This should also work for updating pip:

pip install --upgrade pip
apt-get remove python-pip