Let admins do update.

Author: rikba

install/prepare-jenkins-slave.sh

@@ -2,7 +2,6 @@
 echo "Running the prepare script for polygon_coverage_planning.";
 ROS_VERSION=`rosversion -d`
 echo "ROS version: ${ROS_VERSION}"
-sudo apt update -y
 
 # Build dependencies.
 sudo apt-get install -y python-wstool python-catkin-tools