Adding eStopReasonThreadExiting and fixing the handling of this state on Linux.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@170800 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Target/ThreadPlanStepInRange.cpp b/source/Target/ThreadPlanStepInRange.cpp
index 1e51245..d4324b6 100644
--- a/source/Target/ThreadPlanStepInRange.cpp
+++ b/source/Target/ThreadPlanStepInRange.cpp
@@ -384,6 +384,7 @@
         case eStopReasonSignal:
         case eStopReasonException:
         case eStopReasonExec:
+        case eStopReasonThreadExiting:
             {
                 LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
                 if (log)