Revert "Bump libyaml version."

This reverts commit 56b8453c9c603ed6460673b2b73f113e2c0fe2e4.

Conflicts:
	bosh-stemcell/spec/stemcells/ubuntu_spec.rb
formatting
extracted deployment manifest parsing into its own class

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
Adding final release for build 2150