Revert r296730, "cmake: Configure the ThinLTO cache directory when using ELF lld or gold."
Revert r296730, "cmake: Configure the ThinLTO cache directory when using ELF lld or gold."

Causes a build failure on the clang-with-thin-lto-ubuntu bot.
http://lab.llvm.org:8011/builders/clang-with-thin-lto-ubuntu/builds/2117/steps/build-stage3-compiler/logs/stdio

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@296850 91177308-0d34-0410-b5e6-96231b3b80d8

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