Update PlatformDarwinKernel::GetMacDirectoriesToSearch to also try
/Volumes/KernelDebugKit (the default mount point for the Kernel Debug
Kit dmgs).


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@179058 91177308-0d34-0410-b5e6-96231b3b80d8