Calling the base class constructor from the derived class' initializer list.  This matches DenseMap's behavior, and silences some warnings.
Calling the base class constructor from the derived class' initializer list.  This matches DenseMap's behavior, and silences some warnings.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@188528 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap,apple/swift-llvm,apple/swift-llvm,chubbymaggie/asap,chubbymaggie/asap,llvm-mirror/llvm,dslab-epfl/asap,llvm-mirror/llvm,apple/swift-llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,chubbymaggie/asap,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,dslab-epfl/asap,dslab-epfl/asap,GPUOpen-Drivers/llvm,chubbymaggie/asap,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,dslab-epfl/asap,dslab-epfl/asap,llvm-mirror/llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap