Bug 951565: Use fixed revision for device-mako on v1.2

v1.2 breaks with later changes to device-mako. The easiest solution
is to checkout a fix revision on v1.2.

Change-Id: Ie1d99f5755ee9379ab3161ad668ae0c060d0c6d0
Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>