devserver: fixed invalid log method name
devserver: fixed invalid log method name

BUG=None
TEST=Unit tests; runs with log message printed correctly

Change-Id: I231120a38dfac3549bd14bf43b0cd5cac2775c2b
Reviewed-on: https://gerrit.chromium.org/gerrit/33982
Reviewed-by: Scott Zawalski <d0bc454f32175e2361d26fbdb5930ff6be11acc5@chromium.org>
Tested-by: Gilad Arnold <a0dab390cfdc583218cee97b60c5c4eb1be355d2@chromium.org>
Commit-Ready: Gilad Arnold <a0dab390cfdc583218cee97b60c5c4eb1be355d2@chromium.org>

marineam/coreos-dev-util,mgireesh05/dev-util,mgireesh05/dev-util,coreos/dev-util,coreos/dev-util,mgireesh05/dev-util,coreos/dev-util,marineam/coreos-dev-util