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/ThreadPlanStepOverRange.cpp b/source/Target/ThreadPlanStepOverRange.cpp
index 66754d2..7851f70 100644
--- a/source/Target/ThreadPlanStepOverRange.cpp
+++ b/source/Target/ThreadPlanStepOverRange.cpp
@@ -320,6 +320,7 @@
         case eStopReasonSignal:
         case eStopReasonException:
         case eStopReasonExec:
+        case eStopReasonThreadExiting:
         default:
             if (log)
                 log->PutCString ("ThreadPlanStepInRange got asked if it explains the stop for some reason other than step.");