add curl option -k for certificate problems

scripts/prepare_workload.sh

 #!/bin/bash
 #cut the workload for our experiments
-curl -L -o - http://www.cs.huji.ac.il/labs/parallel/workload/l_metacentrum2/METACENTRUM-2013-3.swf.gz | gunzip > workload/METACENTRUM-2013-3.swf
+curl -L -o - http://www.cs.huji.ac.il/labs/parallel/workload/l_metacentrum2/METACENTRUM-2013-3.swf.gz -k | gunzip > workload/METACENTRUM-2013-3.swf
 jun1=44578794;
 nov30=60393593;
 nb_hour=15;