Fix virtualenv error due to Ubuntu patches applied on python package

See pypa/pip#1074

Author: Gilles Rosenbaum

gcd-django.conf

@@ -20,6 +20,6 @@ setuid vagrant
 setgid vagrant
 
 script
-    . /usr/local/virtualenv/bin/activate
+    . /opt/virtualenv/bin/activate
     exec ./manage.py runserver 0.0.0.0:8000 >> /vagrant/gcd-django.log 2>&1
 end script

tools/scripts/index.sh

@@ -4,6 +4,6 @@
 # Originally written by adia (https://github.com/adia)
 # Updated by grosenbaum (http://github.com/grosenbaum)
 
-. /usr/local/virtualenv/bin/activate
+. /opt/virtualenv/bin/activate
 cd /vagrant/www
 ./manage.py rebuild_index --noinput

tools/scripts/init-db.sh

@@ -4,7 +4,7 @@
 # Originally written by adia (https://github.com/adia)
 # Updated by grosenbaum (http://github.com/grosenbaum)
 
-. /usr/local/virtualenv/bin/activate
+. /opt/virtualenv/bin/activate
 cd /vagrant/www
 ./manage.py syncdb --migrate --noinput
 ./manage.py loaddata users

tools/scripts/init-django.sh

@@ -4,6 +4,6 @@
 # Originally written by adia (https://github.com/adia)
 # Updated by grosenbaum (http://github.com/grosenbaum)
 
-. /usr/local/virtualenv/bin/activate
+. /opt/virtualenv/bin/activate
 cd /vagrant/www
 pip install -U -r requirements.txt --allow-all-external --allow-unverified rbtools --allow-unverified python-graph-core