Convert subunit v1 log results to v2 format.

* modules/jenkins/files/slave_scripts/run-unittests.sh: Generating html
from subunit v1 files is much slower than generating them from subunitv2
files because parsing v2 with the v2 parser is much faster than parsing
v1 with the v2 parser and feeding the leftovers through a v1 parser.
Due to this time difference convert v1 files to v2 before parsing them
to generate html.

Change-Id: I7264d68089fb40de62e47660fe1f31c9adcabdb0