Backed out 10 changesets (bug 1712151, bug 1724279, bug 1730712, bug 1717051,...

Backed out 10 changesets (bug 1712151, bug 1724279, bug 1730712, bug 1717051, bug 1723031, bug 1731145) for causing failures on test_yaml.py
Backed out changeset 7f64d538701b (bug 1723031)
Backed out changeset 394152994966 (bug 1723031)
Backed out changeset 9bfeb01bcc9a (bug 1723031)
Backed out changeset 3d283616a57d (bug 1730712)
Backed out changeset bc677b409650 (bug 1724279)
Backed out changeset 784c94c2f528 (bug 1723031)
Backed out changeset 6e1bde40e3b4 (bug 1723031)
Backed out changeset 7adf7e2136a3 (bug 1712151)
Backed out changeset 2aef162b9a1b (bug 1717051)
Backed out changeset 9beeb6d3d95b (bug 1731145)