[NFC] Remove lldb_utility namespace.

While generating the Doxygen I noticed this lone namespace that has one
class and one function in it. This moves them into lldb_private.

llvm-svn: 369485
diff --git a/lldb/source/Core/Debugger.cpp b/lldb/source/Core/Debugger.cpp
index 673de95..e3cd18a 100644
--- a/lldb/source/Core/Debugger.cpp
+++ b/lldb/source/Core/Debugger.cpp
@@ -270,7 +270,7 @@
     // FIXME it would be nice to have "on-change" callbacks for properties
     if (property_path == g_debugger_properties[ePropertyPrompt].name) {
       llvm::StringRef new_prompt = GetPrompt();
-      std::string str = lldb_utility::ansi::FormatAnsiTerminalCodes(
+      std::string str = lldb_private::ansi::FormatAnsiTerminalCodes(
           new_prompt, GetUseColor());
       if (str.length())
         new_prompt = str;
@@ -345,7 +345,7 @@
   m_collection_sp->SetPropertyAtIndexAsString(nullptr, idx, p);
   llvm::StringRef new_prompt = GetPrompt();
   std::string str =
-      lldb_utility::ansi::FormatAnsiTerminalCodes(new_prompt, GetUseColor());
+      lldb_private::ansi::FormatAnsiTerminalCodes(new_prompt, GetUseColor());
   if (str.length())
     new_prompt = str;
   GetCommandInterpreter().UpdatePrompt(new_prompt);