IndexDiff: support state [removed, untracked] IndexDiff was extended to detect files which are both removed from the index and untracked. Before this change these files were only added to the removed collection. Change-Id: I971d8261d2e8932039fce462b59c12e143f79f90 Signed-off-by: Jens Baumgart <jens.baumgart@sap.com> Signed-off-by: Shawn O. Pearce <spearce@spearce.org>