[CONTINUUM-2718] download text during a distributed build

Distributed build has a different method of populating the build output,
which is shown in the main method that sets buildOutput. Reuse that for both
methods instead of re-reading the text file

git-svn-id: https://svn.apache.org/repos/asf/continuum/trunk@1599873 13f79535-47bb-0310-9956-ffa450edef68