Move initializaton of $session_id from after to before block

This should solve the problem of Jenkins jobs pointing to wrong Sauce
jobs, or Jenkins jobs having http://saucelabs.com/jobs/ link

Bug: 46888
Change-Id: I976e35cbc970fa15be667a0e4b47840ae552b371
Merge "Move initializaton of $session_id from after to before block"