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/ThreadPlanBase.cpp b/source/Target/ThreadPlanBase.cpp
index ebf4686..4440837 100644
--- a/source/Target/ThreadPlanBase.cpp
+++ b/source/Target/ThreadPlanBase.cpp
@@ -146,7 +146,8 @@
                 log->Printf("Base plan discarding thread plans for thread tid = 0x%4.4" PRIx64 " (exec.)", m_thread.GetID());
             m_thread.DiscardThreadPlans(false);
             return true;
-            
+
+        case eStopReasonThreadExiting:
         case eStopReasonSignal:
             if (stop_info_sp->ShouldStop(event_ptr))
             {