Add ".sahara" suffix automatically to swift URLs in workflows

Currently Swift URLs accessed from Hadoop must be of the form
"swift://container.service/object", where for Sahara the service
name is "sahara".  Hadoop uses the service name to look up credentials
for accessing the data.

This mechansism puts different constraints on swift urls used for
job binaries (accessed from Sahara) and data sources (accessed from
Hadoop) which may be unexpected.

This CR automatically adds the ".sahara" suffix to swift URLs when
the workflow is generated.

Change-Id: I9afc25b2354c008dc5357058bf980cb0f05da864
Merge "Add ".sahara" suffix automatically to swift URLs in workflows"