[telemetry] Comment out unused import to fix PyLint.

BUG=None.
TEST=None.
TBR=pfeldman

Review URL: https://codereview.chromium.org/28733010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229505 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229505