Experiment with printing a warning message when lldb is unable to
find a binary on the debugger-host during a kernel debug session
for a kernel extension (kext).  This may prove to be too verbose
in typical usage, particularly if there are many third-party kexts.
We'll try this and see how it works.

<rdar://problem/13080833> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175494 91177308-0d34-0410-b5e6-96231b3b80d8