Install dev-util/lcov again.
Install dev-util/lcov again.

Since the dependency problem was resolved, we can now install it and use
it for generating coverage reports.

BUG=None
TEST=Builds dev-util/lcov

Change-Id: I02cc1aa8cedea3da1b985732f6fbb2d2ba58cf89
Reviewed-on: https://gerrit.chromium.org/gerrit/25544
Reviewed-by: Don Garrett <546ec366615570e68497e3c5df9092106a9808f4@chromium.org>
Commit-Ready: Gilad Arnold <a0dab390cfdc583218cee97b60c5c4eb1be355d2@chromium.org>
Tested-by: Gilad Arnold <a0dab390cfdc583218cee97b60c5c4eb1be355d2@chromium.org>

marineam/update_engine,endocode/update_engine,mjg59/update_engine,endocode/update_engine,marineam/update_engine,mjg59/update_engine,endocode/update_engine,marineam/update_engine,marineam/update_engine,mjg59/update_engine