Replace ubuntu images with ones generated from mkimage-debootstrap (dotcloud/docker#2222)

library/ubuntu

@@ -1,7 +1,12 @@
-latest	git://github.com/dotcloud/ubuntu-quantal
-quantal	git://github.com/dotcloud/ubuntu-quantal
-12.10	git://github.com/dotcloud/ubuntu-quantal
-precise	git://github.com/shin-/ubuntu				B:precise
-12.04	git://github.com/shin-/ubuntu				B:precise
-raring	git://github.com/shin-/ubuntu				B:raring
-13.04	git://github.com/shin-/ubuntu				B:raring
+latest	git://github.com/tianon/docker-brew-ubuntu	C:96fb1a4775743da97ef914f9bd91ac5d59eaf3d6
+precise	git://github.com/tianon/docker-brew-ubuntu	C:96fb1a4775743da97ef914f9bd91ac5d59eaf3d6
+12.04	git://github.com/tianon/docker-brew-ubuntu	C:96fb1a4775743da97ef914f9bd91ac5d59eaf3d6
+
+quantal	git://github.com/tianon/docker-brew-ubuntu	C:c4e5dee217efe78bb773223b9f4a2ebbe1226caf
+12.10	git://github.com/tianon/docker-brew-ubuntu	C:c4e5dee217efe78bb773223b9f4a2ebbe1226caf
+
+raring	git://github.com/tianon/docker-brew-ubuntu	C:80e86d8bb6ff135805de6f1f56d3998b9aabe1ff
+13.04	git://github.com/tianon/docker-brew-ubuntu	C:80e86d8bb6ff135805de6f1f56d3998b9aabe1ff
+
+saucy	git://github.com/tianon/docker-brew-ubuntu	C:c8ba2f1f5883b528a92cfa705e670dea8ddeaf0d
+13.10	git://github.com/tianon/docker-brew-ubuntu	C:c8ba2f1f5883b528a92cfa705e670dea8ddeaf0d