INFINITY-2917 CI: Include timestamp in fetched log filenames (#2037)
INFINITY-2917 CI: Include timestamp in fetched log filenames (#2037)

* INFINITY-2917 CI: Include timestamp in fetched log filenames

Puts the timestamp at the start of the file so that files are sorted by time.

We only have access to month/day/hour/min, so here's what it'll look like:
`0104_1709.hello-world.0fe39302-f18b-11e7-a6f9-ae11b3b25138.stdout`

* Use strftime()

* Fix wrong var name

* Use proper regex for parsing 'task ls --long'

vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,mesosphere/dcos-commons,vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,vishnu2kmohan/dcos-commons