Add "fastboot --version".

So bug reporters can actually tell us what they're running.

Bug: http://b/21558406
Bug: http://b/21583225
Change-Id: If2a4ae97b4792aa321566603ce2c354a72d32307
(cherry picked from commit 379646b2ca2cf681be3489eb74a421b3f8c80e26)
2 files changed