This patch fixes a bug where the YAML Output class emitted
a sequence of flow sequences without the '-' characters.
Before:
seq:
[ a, b ]
[ c, d ]
After:
seq:
- [ a, b ]
- [ c, d ]
Reviewers: Justin Bogner
Differential Revision: http://reviews.llvm.org/D9206
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236329 91177308-0d34-0410-b5e6-96231b3b80d8