Print response body when a 400 error is received in results_dashboard.py.
Print response body when a 400 error is received in results_dashboard.py.

BUG=

Review URL: https://codereview.chromium.org/637713002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@292362 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build