Change dashboard upload exception to warning for the time being.
Change dashboard upload exception to warning for the time being.

BUG=222607
TBR=iannucci@chromium.org


Review URL: https://chromiumcodereview.appspot.com/12845009

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@189489 0039d316-1c4b-4281-b951-d872f2087c98

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