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/Commands/CommandObjectTarget.cpp b/lldb/source/Commands/CommandObjectTarget.cpp
index c8871c8..a2df490 100644
--- a/lldb/source/Commands/CommandObjectTarget.cpp
+++ b/lldb/source/Commands/CommandObjectTarget.cpp
@@ -19,6 +19,7 @@
 #include "lldb/Core/Timer.h"
 #include "lldb/Core/ValueObjectVariable.h"
 #include "lldb/DataFormatters/ValueObjectPrinter.h"
+#include "lldb/Host/OptionParser.h"
 #include "lldb/Host/StringConvert.h"
 #include "lldb/Host/Symbols.h"
 #include "lldb/Interpreter/Args.h"