Stop doing any magic cloning of neutron during CI

With https://review.openstack.org/185739 merged to neutron we can no
longer have neutron in requirements.txt

Adopting the solution developed by Doug Wiegley for LBaaS:
c61f920f2a54fd829ee37484b3743ab77b909847

Update how the tools/add_neutron_patches.sh script is invoked.

Change-Id: I0df48369bdc9de22be51af4e7c4ea9ce4255cd2a

requirements.txt

@@ -4,4 +4,3 @@
 
 pbr>=0.6,!=0.7,<1.0
 Babel>=1.3
--e git://git.openstack.org/openstack/neutron.git#egg=neutron

tools/add_neutron_patches.sh

@@ -2,17 +2,17 @@
 
 echo "Adding neutron patches into the testing env"
 
-DIRECTORY="$1/src/neutron"
+NEUTRON_SRC="$1"
 LIST_SRC="$2/test-patches.txt"
 
-echo "Checking Directory Existance: $DIRECTORY"
+echo "Checking Directory Existence: $NEUTRON_SRC"
 
-if [ ! -d "$DIRECTORY" ]; then
-  echo "Directory $DIRECTORY does not exist, aborting..."
+if [ ! -d "$NEUTRON_SRC" ]; then
+  echo "Directory $NEUTRON_SRC does not exist, aborting..."
   exit 1
 fi
 
-cd $DIRECTORY
+cd $NEUTRON_SRC
 
 # Ensure we're on toxBranch not master or other branches
 git checkout -b toxBranch 2> /dev/null

tools/tox_install.sh

@@ -0,0 +1,45 @@
+#!/bin/sh
+
+# Many of neutron's repos suffer from the problem of depending on neutron,
+# but it not existing on pypi.
+
+# This wrapper for tox's package installer will use the existing package
+# if it exists, else use zuul-cloner if that program exists, else grab it
+# from neutron master via a hard-coded URL. That last case should only
+# happen with devs running unit tests locally.
+
+# From the tox.ini config page:
+# install_command=ARGV
+# default:
+# pip install {opts} {packages}
+
+ZUUL_CLONER=/usr/zuul-env/bin/zuul-cloner
+neutron_installed=$(echo "import neutron" | python 2>/dev/null ; echo $?)
+
+set -ex
+
+cwd=$(/bin/pwd)
+
+if [ $neutron_installed -eq 0 ]; then
+    echo "ALREADY INSTALLED" > /tmp/tox_install.txt
+    echo "Neutron already installed; using existing package"
+elif [ -x "$ZUUL_CLONER" ]; then
+    echo "ZUUL CLONER" > /tmp/tox_install.txt
+    cd /tmp
+    $ZUUL_CLONER --cache-dir \
+        /opt/git \
+        git://git.openstack.org \
+        openstack/neutron
+    cd openstack/neutron
+    $cwd/tools/add_neutron_patches.sh /tmp/openstack/neutron $cwd
+    pip install -e .
+    cd "$cwd"
+else
+    echo "PIP HARDCODE" > /tmp/tox_install.txt
+    pip install -U -egit+https://git.openstack.org/openstack/neutron#egg=neutron
+    $cwd/tools/add_neutron_patches.sh $VIRTUAL_ENV/src/neutron $cwd
+    pip install -U -e $VIRTUAL_ENV/src/neutron
+fi
+
+pip install -U $*
+exit $?

tox.ini

@@ -9,11 +9,11 @@ skipsdist = True
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
 usedevelop = True
-install_command = pip install -r requirements.txt -U {opts} {packages}
-deps = -r{toxinidir}/test-requirements.txt
+install_command = {toxinidir}/tools/tox_install.sh {opts} {packages}
+deps = -r{toxinidir}/requirements.txt
+       -r{toxinidir}/test-requirements.txt
 whitelist_externals = sh
 commands =
-  sh {toxinidir}/tools/add_neutron_patches.sh {envdir} {toxinidir}
   sh tools/pretty_tox.sh '{posargs}'
 # there is also secret magic in pretty_tox.sh which lets you run in a fail only
 # mode. To do this define the TRACE_FAILONLY environmental variable.