gold plugin: move target initialization to the top of the onload function.
gold plugin: move target initialization to the top of the onload function.

On at least my machine, ar does not register an all symbols read hook (which
previously triggered target initialization), but it does register a claim
files hook, which depends on the targets being initialized.

Differential Revision: http://reviews.llvm.org/D4372

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@212303 91177308-0d34-0410-b5e6-96231b3b80d8

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