Removing repetitive bower version message on deploy.

When building the application the following messages appear:

-----> Writing config/database.yml to read from DATABASE_URL
-----> Using bower version: 1.2.7
-----> Installing JavaScript dependencies using bower 1.2.7

There is an unecessary repetition on bower version, this removes this
message, like:

-----> Writing config/database.yml to read from DATABASE_URL
-----> Installing JavaScript dependencies using Bower 1.2.7