Remove now duplicate sync;sleep 5

Since https://review.openstack.org/#/c/196252/ merged, nodepool
injects a sync;sleep 5 after running the scripts, so having it in the
scripts is a double sleep.

Change-Id: Ie7a9315e6de67625eca15b45f1662e4c63f8bc10

nodepool/scripts/prepare_devstack.sh

@@ -20,6 +20,3 @@ cd /opt/nodepool-scripts/
 ./install_devstack_dependencies.sh
 DISTRIB_CODENAME=$(lsb_release -sc)
 python ./cache_devstack.py $DISTRIB_CODENAME
-
-sync
-sleep 5

nodepool/scripts/prepare_node.sh

@@ -251,6 +251,3 @@ sudo -H /usr/zuul-swift-logs-env/bin/pip install python-magic argparse \
 # https://bugs.launchpad.net/ubuntu/+source/python2.7/+bug/839588
 sudo -H virtualenv /usr/os-testr-env
 sudo -H /usr/os-testr-env/bin/pip install os-testr
-
-sync
-sleep 5

nodepool/scripts/prepare_node_tripleo.sh

@@ -25,6 +25,3 @@ export THIN='true'
 sudo ip link set mtu 1458 dev eth0
 ./prepare_node.sh "$HOSTNAME"
 sudo -u jenkins -i /opt/nodepool-scripts/prepare_tripleo.sh "$HOSTNAME"
-
-sync
-sleep 5

nodepool/scripts/prepare_tripleo.sh

@@ -60,6 +60,3 @@ else
     echo "Unsupported distro."
     exit 1
 fi
-
-sync
-sleep 5

nodepool/scripts/restrict_memory.sh

@@ -29,6 +29,3 @@ if [ -f /etc/default/grub ] ; then
 elif [ -f /boot/grub/grub.conf ] ; then
     sudo sed -i -e 's/^timeout=[0-9]\+/timeout=0/' -e 's/\(^\s\+kernel.*\)/\1 mem=8G/' /boot/grub/grub.conf
 fi
-
-sync
-sleep 5