Check YAML files for syntax errors
Check YAML files for syntax errors

Related story:
  https://www.pivotaltracker.com/story/show/18189131

Change-Id: Ie7b63bf8fa1e37050448f654544367702d4bfa65

TheSooth/overcommit,oxocode/overcommit,TheSooth/overcommit,blech75/overcommit,oxocode/overcommit,gnagel/overcommit,gnagel/overcommit,blech75/overcommit