Ensure virtualenv binaries use relative paths

This works around the shebang/virtualenv path length limit.
See: pypa/pip#1773

Connects rcbops/u-suk-dev#1080

pipeline-steps/common.groovy

@@ -20,6 +20,7 @@ def install_ansible(){
     # installing pip resets the shebang to be absolute
     virtualenv --relocatable .venv
     pip install -U ansible pyrax
+    virtualenv --relocatable .venv
   """
 }
 

pipeline-steps/horizon.groovy

@@ -32,13 +32,15 @@ def mitaka_prep() {
     if [[ ! -d ".venv" ]]; then
         pip install virtualenv
         virtualenv .venv
+        virtualenv --relocatable .venv
     fi
     source .venv/bin/activate
 
     mv ~/.pip/pip.conf ~/.pip/pip.conf.bak
     pip install selenium==2.53.1
     pip install -r test-requirements.txt
     pip install -r requirements.txt
+    virtualenv --relocatable .venv
     mv ~/.pip/pip.conf.bak ~/.pip/pip.conf
     """
   }

pipeline-steps/kibana.groovy

@@ -28,9 +28,11 @@ def kibana_prep(){
     if [ -f ~/.pip/pip.conf ]; then
       mv ~/.pip/pip.conf ~/.pip/pip.conf.bak
       pip install -r requirements.txt
+      virtualenv --relocatable .venv
       mv ~/.pip/pip.conf.bak ~/.pip/pip.conf
     else
       pip install -r requirements.txt
+      virtualenv --relocatable .venv
     fi
     """
   }

pipeline-steps/ssh_slave.groovy

@@ -47,6 +47,7 @@ def destroy(Map args){
       sh """
         . ../playbooks/.venv/bin/activate
         pip install jenkinsapi
+        virtualenv --relocatable ../playbooks/.venv
         python jenkins_node.py \
           delete --name "${args.instance_name}"
       """

playbooks/setup-jenkins-slave.yml

@@ -76,6 +76,7 @@
         cd  {{ lookup('env', 'WORKSPACE') }}/rpc-gating/playbooks
         . .venv/bin/activate
         pip install jenkinsapi
+        virtualenv --relocatable .venv
         python ../scripts/jenkins_node.py \
           create \
           --name {{inventory_hostname}} \

rpc-jobs/install-jenkins-plugins.yml

@@ -20,6 +20,7 @@
             sh """#!/bin/bash
               . .venv/bin/activate
               pip install urllib3==1.18.1
+              virtualenv --relocatable .venv
             """
             common.venvPlaybook(
               playbooks: ["playbooks/install_jenkins_plugins.yml"],

rpc-jobs/jjb-setup.yml

@@ -40,6 +40,7 @@
             source .venv/bin/activate
 
             pip install jenkins-job-builder
+            virtualenv --relocatable .venv
 
             cat > jenkins_jobs.ini << EOF
             [job-builder]