Summary:
This change adds an automatic shared files update step during the jenkins
build. This guarantees, that we always have the latest DB data packaged
into the installers.
The updated files will be written into the source directory, so install
step will automatically pick up the updated ones.
ref T158
Reviewers: #swift_pilot_client, msutcliffe
Reviewed By: #swift_pilot_client, msutcliffe
Subscribers: jenkins
Maniphest Tasks: T158
Differential Revision: https://dev.swift-project.org/D56
