Merge "CI: drop pip --upgrade flag in tox.ini"

tox.ini

@@ -10,7 +10,7 @@ addopts = --verbose -p no:requests_mock
 
 [testenv]
 usedevelop = True
-install_command = pip install -U {opts} {packages}
+install_command = pip install {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
@@ -188,9 +188,6 @@ deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt
   -r{toxinidir}/requirements.txt
-# Drop the --upgrade flag so we don't accidentally drag anything forward when
-# we install swift
-install_command = pip install {opts} {packages}
 
 [testenv:pdf-docs]
 basepython = python3