Remove unused initialization.
clang static analyzer fixit.

llvm-svn: 219909
diff --git a/lldb/source/Target/Thread.cpp b/lldb/source/Target/Thread.cpp
index 17f0619..4171cc7 100644
--- a/lldb/source/Target/Thread.cpp
+++ b/lldb/source/Target/Thread.cpp
@@ -1690,7 +1690,7 @@
                          bool include_internal,
                          bool ignore_boring_threads) const
 {
-    uint32_t stack_size = m_plan_stack.size();
+    uint32_t stack_size;
 
     if (ignore_boring_threads)
     {