Fixed hhvm breaking all the things

See... this is why we need to move away from apt-get.
Why would `apt-get install` START a service? Did I type
"run" or "start" anywhere??? No... I didn't.

toolset/setup/linux/languages/hhvm.sh

@@ -11,6 +11,8 @@ echo deb http://dl.hhvm.com/ubuntu `lsb_release -sc` main | sudo tee /etc/apt/so
 sudo apt-get update
 sudo apt-get install -y hhvm
 
+sudo service stop hhvm
+
 echo "" > $IROOT/hhvm.installed
 
 source $IROOT/hhvm.installed