Install pip distribute as a workaround for buggy/old setuptools typically in ubuntu 14.04

Change-Id: Iaced563abdc6d43288347c239968121dc603bb44
diff --git a/src/test/setup/prerequisites.sh b/src/test/setup/prerequisites.sh
index c4443e4..dbe5206 100755
--- a/src/test/setup/prerequisites.sh
+++ b/src/test/setup/prerequisites.sh
@@ -97,9 +97,11 @@
     mkdir -p $setup_path/venv
     virtualenv $setup_path/venv
     echo "Installing cord-tester pip packages on the virtual environment"
+    $setup_path/venv/bin/pip install -U distribute
     $setup_path/venv/bin/pip install -r $setup_path/requirements.txt
 else
     echo "Installing cord-tester pip packages on the host"
+    pip install -U distribute
     pip install -r $setup_path/requirements.txt
 fi