Adding DVLOG for unknown wallet errors to see what the unknown string is.

BUG=None

Review URL: https://codereview.chromium.org/118003003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243025 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243025