Add ability to pass a base test root and create results dirs relative.

Add ability to pass a base test root and create results dirs relative.

Sets up dir paths as follows:

test_root/test_name i.e. SimpleUpdate/<num>_stage 

For example:

test_root/testNormalUpdateKeepStateful/2_verify/...test_results...
corresponds to the second invocation of verify image.  The test
results for this stage are stored here.

This is a predecessor for storing arbitrary logs e.g. update into
this test results root.

Change-Id: I7183420b5dcb0d6971aa508a338c048c3557e359

BUG=chromium-os:12211
TEST=With simple a full vm test suite w/ w/out explicit test root
set.

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=b54301b

[sosa, 2011-03-04 18:48:13]

For some reason I thought I published this yesterday.

[sosa, 2011-03-04 19:14:42]

Added test_results_root to ctest as well.

[dgarrett, 2011-03-04 22:31:12]

LGTM with a couple of notes.

http://codereview.chromium.org/6614029/diff/3001/bin/au_test_harness/cros_au_...
File bin/au_test_harness/cros_au_test_harness.py (right):

http://codereview.chromium.org/6614029/diff/3001/bin/au_test_harness/cros_au_...
bin/au_test_harness/cros_au_test_harness.py:253: if leftover_args:
parser.error('Found unsupported flags: % s' % leftover_args)
I think that space is put there by mistake, though it seems to have no effect
for non-integers.

http://codereview.chromium.org/6614029/diff/3001/bin/au_test_harness/cros_au_...
bin/au_test_harness/cros_au_test_harness.py:265: error_msg = ('Could not find %
s key.  Both private and public keys must be '
80 characters, the space looks like an error, and there is nothing %'d into the
%s anyway.