Apply chirp_root for output files as well as input files.
Apply chirp_root for output files as well as input files.

We are already expecting the [full path](https://github.com/matz-e/lobster/blob/master/lobster/job.py#L93) to the stageout directory. Consider:
chirp_root = /a/b
stageout location = /a/b/c/d

Before, this configuration sent files to /a/b/c/d/a/b/c/d
Now, this configuration sends files to /a/b/c/d

matz-e/lobster,matz-e/lobster,matz-e/lobster