Silence C4715 warning from MSVC (NFC).
Silence C4715 warning from MSVC (NFC).

The warning started triggering after r317560.
This commit silences it in the same way as previously done in a similar
situation, see
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20140915/236088.html


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@317568 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm