Fix bug in Host::getLLDBPath() due to misusing Twine
- use SmallString instead
- original implementation resulted in incorrect behaviour of lldb -P

Fix by Kal Conley!



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@187818 91177308-0d34-0410-b5e6-96231b3b80d8