Delete some more dead includes.

This breaks the cycle between Target and PluginLanguageC++, reducing
the overall cycle count from 43 to 42.

llvm-svn: 298561
diff --git a/lldb/source/Interpreter/OptionGroupOutputFile.cpp b/lldb/source/Interpreter/OptionGroupOutputFile.cpp
index 35e6f52..7b0ee61 100644
--- a/lldb/source/Interpreter/OptionGroupOutputFile.cpp
+++ b/lldb/source/Interpreter/OptionGroupOutputFile.cpp
@@ -13,6 +13,7 @@
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
+#include "lldb/Host/OptionParser.h"
 
 using namespace lldb;
 using namespace lldb_private;