Export job name to the shell script, too
Export job name to the shell script, too

self.job_name is something like "shell_script-${hostname}-${number}",
and job_arguments doesn't contain anything like a job name, either.

Change-Id: I775609990c740c29016abe89c5dce9ab81ca61b9

stackforge/turbo-hipster,stackforge/turbo-hipster