[lldb/Plugin] Don't define initializers inside lldb_private

This should fix the Windows build.

lldb/include/lldb/Core/PluginManager.h

@@ -23,10 +23,8 @@
 #include <stdint.h>
 
 #define LLDB_PLUGIN(PluginName)                                                \
-  namespace lldb_private {                                                     \
   void lldb_initialize_##PluginName() { PluginName::Initialize(); }            \
   void lldb_terminate_##PluginName() { PluginName::Terminate(); }              \
-  }
 
 // FIXME: Generate me with CMake
 #define LLDB_PLUGIN_INITIALIZE(PluginName)                                     \