Fix six package on opensuse for pip 10

openSUE Leap 15.0 and 15.1 both provide python3-six version 1.11.0.
Since version 1.12.0 was released, pip>=10 recognizes the version
difference and tries to uninstall the distro-provided version and fails.
This change adds another hack to remove the egg-info file for the six
library so that pip can manage it directly. We also have to wait to
install os-testr until after the fixup has happened since trying to
install it triggers the issue.

Change-Id: I4649abe06b5893a5251bfcdd4234abccde6ceda2
diff --git a/stack.sh b/stack.sh
index 11783fd..b7b37e2 100755
--- a/stack.sh
+++ b/stack.sh
@@ -796,9 +796,6 @@
     PYPI_ALTERNATIVE_URL=${PYPI_ALTERNATIVE_URL:-""} $TOP_DIR/tools/install_pip.sh
 fi
 
-# Install subunit for the subunit output stream
-pip_install -U os-testr
-
 TRACK_DEPENDS=${TRACK_DEPENDS:-False}
 
 # Install Python packages into a virtualenv so that we can track them
@@ -816,6 +813,9 @@
 source $TOP_DIR/tools/fixup_stuff.sh
 fixup_all
 
+# Install subunit for the subunit output stream
+pip_install -U os-testr
+
 if [[ "$USE_SYSTEMD" == "True" ]]; then
     pip_install_gr systemd-python
     # the default rate limit of 1000 messages / 30 seconds is not
diff --git a/tools/fixup_stuff.sh b/tools/fixup_stuff.sh
index d7b824c..d298937 100755
--- a/tools/fixup_stuff.sh
+++ b/tools/fixup_stuff.sh
@@ -256,6 +256,7 @@
     # overwriting works.  So this hacks around those packages that
     # have been dragged in by some other system dependency
     sudo rm -rf /usr/lib/python3.6/site-packages/ply-*.egg-info
+    sudo rm -rf /usr/lib/python3.6/site-packages/six-*.egg-info
 }
 
 # The version of pip(1.5.4) supported by python-virtualenv(1.11.4) has