Only replace python when re-initializing the venv

We reinitialize the venv to ensure that the right version of
python is in the venv, but we do not want virtualenv to also
replace pip, setuptools and wheel so we tell it not to. If we
don't do this then virtualenv will install the latest available
version, which is not what we want.

Change-Id: Icc757ac36b298e46c0f257cd8304ac8553b85ee3
Partial-Bug: #1764470

tasks/molteniron_install.yml

@@ -103,11 +103,22 @@
   delay: 2
   when: molteniron_developer_mode | bool
 
+# NOTE(odyssey4me):
+# We reinitialize the venv to ensure that the right
+# version of python is in the venv, but we do not
+# want virtualenv to also replace pip, setuptools
+# and wheel so we tell it not to.
+# We do not use --always-copy for CentOS/SuSE due
+# to https://github.com/pypa/virtualenv/issues/565
 - name: Update virtualenv path
   shell: |
     find {{ molteniron_bin }} -name \*.pyc -delete
     sed -si '1s/^.*python.*$/#!{{ molteniron_bin | replace ('/','\/') }}\/python/' {{ molteniron_bin }}/*
-    virtualenv {{ molteniron_bin | dirname }}
+    virtualenv {{ molteniron_bin | dirname }} \
+        {{ (ansible_pkg_mgr == 'apt') | ternary('--always-copy', '') }} \
+        --no-pip \
+        --no-setuptools \
+        --no-wheel
   when:
     - not molteniron_developer_mode | bool
     - molteniron_get_venv | changed