Log javelin into in its own  logfile.

Use a single log file for both javelin create and check

Related devstack-gate change: I787c08506d9a4d12081b5b5b16d752d5147f8e72

Change-Id: Id5c0dfeaf8e7e9ed1d54f51c54e6e5c65b1361fa
Merge "Log javelin into in its own  logfile."