Use the correct call to close down the lockdown connection.

<rdar://problem/14460024>

llvm-svn: 186597
diff --git a/lldb/tools/debugserver/source/RNBSocket.cpp b/lldb/tools/debugserver/source/RNBSocket.cpp
index 13939d5..67dc009 100644
--- a/lldb/tools/debugserver/source/RNBSocket.cpp
+++ b/lldb/tools/debugserver/source/RNBSocket.cpp
@@ -320,10 +320,8 @@
     {
         m_fd_from_lockdown = false;
         m_fd = -1;
-        if (lockdown_deactivate (m_ld_conn) == 0)
-            return rnb_success;
-        else
-            return rnb_err;
+        lockdown_disconnect (m_ld_conn);
+        return rnb_success;
     }
 #endif
     return ClosePort (m_fd, save_errno);