[autotest] Fix unittest -- dev_server.py

GetLatestBuildVersion was trying to call the DevServer constructor with
0 parameters, resulting in failure of the unit test which made use of
this. It looks like GetLatestBuildVersion is deprecated anyway, so this
commit rips out the failing test, and rips out GetLatestBuildVersion.

There are still two site_util scripts that reference
GetLatestBuildVersion, which will need to get fixed or removed --
downloader.py and run_tests.py. I will file a bug about the no longer
working GetLatestBuildVersion.

BUG=chromium-os:37989
TEST=Unit tests now pass.
Change-Id: I4797b70065f9f5c1d42cfb2bd84b45766612d5cd
Reviewed-on: https://gerrit.chromium.org/gerrit/43243
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
Tested-by: Aviv Keshet <akeshet@chromium.org>
4 files changed