Update install.sh to install virtualenv when installing neon

this is required for a case the user asks the user *not* to install Coach in a virtualenv (and then the installer does not install virtualenv, which is required for neon)

install.sh

@@ -191,7 +191,7 @@ if [ ${INSTALL_NEON} -eq 1 ]; then
     cd ..
 
     # Neon
-    sudo -E apt-get install libhdf5-dev libyaml-dev pkg-config clang -y
+    sudo -E apt-get install libhdf5-dev libyaml-dev pkg-config clang virtualenv -y
     git clone https://github.com/NervanaSystems/neon.git
     cd neon && make sysinstall -j
     cd ..