Move PseudoTerminal to the lldb_private namespace

lldb_utility doesn't make sense, as it is no longer even living in the
"utility" module.

llvm-svn: 320346
diff --git a/lldb/source/Plugins/Process/Darwin/DarwinProcessLauncher.cpp b/lldb/source/Plugins/Process/Darwin/DarwinProcessLauncher.cpp
index c6daf6c..6b3d5f6 100644
--- a/lldb/source/Plugins/Process/Darwin/DarwinProcessLauncher.cpp
+++ b/lldb/source/Plugins/Process/Darwin/DarwinProcessLauncher.cpp
@@ -144,7 +144,7 @@
   // Use a fork that ties the child process's stdin/out/err to a pseudo
   // terminal so we can read it in our MachProcess::STDIOThread
   // as unbuffered io.
-  lldb_utility::PseudoTerminal pty;
+  PseudoTerminal pty;
   char fork_error[256];
   memset(fork_error, 0, sizeof(fork_error));
   *pid = static_cast<::pid_t>(pty.Fork(fork_error, sizeof(fork_error)));