run adduser memcache with sudo
run adduser memcache with sudo

the adduser command needs to be run as sudo,
otherwise it fails with the message:

  ./build.sh: line 5: /usr/sbin/adduser: Permission denied

This patch adds sudo to the command.

This patch also adds set -e to the build.sh so that it
will fail and exit if any of its commands fail.

intelsdi-x/swan,intelsdi-x/swan,intelsdi-x/swan