This script can be executed by a developer to download and graft
on the old JGit history, from before we moved the project to the
eclipse.org namespace and the Eclipse Foundation servers.

Executing this script is only necessary if you need to run log or
blame past the migration boundary, and isn't always recommended when
it comes to pushing objects to a remote server.  As mentioned in the
script, it is best to use a specialized repository with this graft,
not your main work repository.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Per CQ 3448 this is the initial contribution of the JGit project
to eclipse.org.  It is derived from the historical JGit repository
at commit 3a2dd9921c8a08740a9e02c421469e5b1a9e47cb.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>