use virtualenv flag to use pinned pip

.circle/0001-pin-python2.7-tests-to-st2-3.3.patch

@@ -0,0 +1,27 @@
+From 054508235bc3a3174ccc074c92829c206f2afb78 Mon Sep 17 00:00:00 2001
+From: Jacob Floyd <cognifloyd@gmail.com>
+Date: Thu, 28 Jan 2021 12:08:33 -0600
+Subject: [PATCH] pin python2.7 tests to st2 3.3
+
+StackStorm 3.3 is the last version to support 2.7. So, use the v3.3
+branch instead of the master branch for the python 2.7 tests.
+---
+ .circle/circle.yml.sample | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/.circle/circle.yml.sample b/.circle/circle.yml.sample
+index 88a0ece..7168dc8 100644
+--- a/.circleci/config.yml
++++ b/.circleci/config.yml
+@@ -14,6 +14,8 @@ jobs:
+       # Don't install various StackStorm dependencies which are already
+       # installed by CI again in the various check scripts
+       ST2_INSTALL_DEPS: "0"
++      # 3.3 is the last version to support python27
++      ST2_BRANCH: "v3.3"
+
+     steps:
+       - checkout
+-- 
+2.26.2
+

.circle/dependencies

@@ -36,13 +36,10 @@ sudo apt-get -y install libldap2-dev libsasl2-dev
 PIP_DEP="pip==20.0.2"
 sudo pip install -U "${PIP_DEP}" setuptools virtualenv
 
-virtualenv ~/virtualenv
+# make sure virtualenv is built with same pip version
+virtualenv --pip "${PIP_DEP}" ~/virtualenv
 source ~/virtualenv/bin/activate
 
-# virtualenv is updating pip. Revert back to our pinned version.
-pip install -U "${PIP_DEP}"
-pip --version
-
 # Install StackStorm requirements
 echo "Installing StackStorm requirements from /tmp/st2/requirements.txt"
 ~/virtualenv/bin/pip install -r "/tmp/st2/requirements.txt"