Add a version field in the bitcode for the summary

Differential Revision: http://reviews.llvm.org/D19456

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267318 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed