finatra - Update .travis.yml configuration for sbt-scoverage
finatra - Update .travis.yml configuration for sbt-scoverage

Problem

Coverage reporting has changed in sbt-scoverage 1.3.5. This
issue highlights the problem:
https://github.com/scoverage/sbt-scoverage/issues/161

Solution

Add the needed step to the travis build configuration to
properly generate coverage reports.

Result

Actual coverage reporting after the travis ci build runs.

RB_ID=811398
TBR=true

syamantm/finatra,twitter/finatra,syamantm/finatra,twitter/finatra,syamantm/finatra,syamantm/finatra,twitter/finatra