[demo-vm-setup] added curl error handling
[demo-vm-setup] added curl error handling

Stop once it's clear the VBox appliance has failed to download:
do not try to interpret S3 server output for HTTP 403 and other
errors as a valid VBox appliance file.

Also made curl to follow HTTP redirects, if any.

cloudera/kudu,cloudera/kudu,helifu/kudu,helifu/kudu,cloudera/kudu,InspurUSA/kudu,cloudera/kudu,helifu/kudu,EvilMcJerkface/kudu,helifu/kudu,helifu/kudu,andrwng/kudu,helifu/kudu,andrwng/kudu,cloudera/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,InspurUSA/kudu,andrwng/kudu,andrwng/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,andrwng/kudu,InspurUSA/kudu,InspurUSA/kudu,helifu/kudu,helifu/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,andrwng/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,cloudera/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,helifu/kudu,cloudera/kudu,andrwng/kudu,andrwng/kudu