fix sudo redirection in setup script

experimental/webtry/setup/webtry_setup.sh

 #!/bin/bash
 #
 # Script to setup a GCE instance to run the webtry server.
 # For full instructions see the README file.
 sudo apt-get install schroot debootstrap monit squid3
 
 # although aufs is being replaced by overlayfs, it's not clear
 # to me if overlayfs is completely supported by schroot yet.
 sudo apt-get install aufs-tools
 
@@ skipping 11 matching lines @@
 
 CHROOT_JAIL=/srv/chroot/webtry_gyp
 # Build the chroot environment
 if [ ! -d ${CHROOT_JAIL} ]; then
         sudo mkdir -p ${CHROOT_JAIL}
 
         sudo debootstrap --variant=minbase wheezy ${CHROOT_JAIL}
         sudo cp setup_jail.sh ${CHROOT_JAIL}/bin
         sudo chmod 755 ${CHROOT_JAIL}/bin/setup_jail.sh
         sudo chroot ${CHROOT_JAIL} /bin/setup_jail.sh
-        sudo echo "none /dev/shm tmpfs rw,nosuid,nodev,noexec 0 0" >> ${CHROOT_JAIL}/etc/fstab
+        sudo sh -c "echo 'none /dev/shm tmpfs rw,nosuid,nodev,noexec 0 0' >> ${CHROOT_JAIL}/etc/fstab"
 fi
 
 # the continue_install script will fetch the latest versions of 
 # skia and depot_tools.  We split up the installation process into 
 # two pieces like this so that the continue_install script can
 # be run independently of this one to fetch and build the latest skia.
 
 ./continue_install.sh
 
 sudo cp ../sys/webtry_init /etc/init.d/webtry
 sudo cp ../sys/webtry_monit /etc/monit/conf.d/webtry
 sudo cp ../sys/webtry_squid /etc/squid3/squid.conf
 sudo chmod 744 /etc/init.d/webtry
 
 # Confirm that monit is happy.
 
 sudo monit -t
 sudo monit reload