Change in yangtools results in exception when loading SFC

While attempting to run the SFC project (integrating with GBP), I got the following exception:

http://pastebin.com/0wQ95Rs8

I cloned yangtools locally and built it using a git hash from yesterday:

commit 98dbda7e7184036e0bc9144c0b2b1b9203a9f500
Author: Tony Tkacik <ttkacik@cisco.com>
Date: Mon Apr 13 18:48:43 2015 +0200

YANGTOOLS-444 - Added Missing space separator for list keys in yin format

Change-Id: Ibb943777604f61dde20bb84fce2a7f13c38333c7
Signed-off-by: Tony Tkacik <ttkacik@cisco.com>

and it works. If I go to the one after it:

commit c7c67c1ad9fbd77e2705345400f1db5b3d46e200
Merge: 98dbda7 6041965
Author: Robert Varga <nite@hq.sk>
Date: Tue Apr 14 10:38:31 2015 +0000

Merge "YANGTOOLS-363: Make sure JSON and XML codecs are not losing constraints."

It fails.