set ntp_ok to no if ntp debugging is not enabled.

Upstream-status: Pending

There is a problem in configure.ac file that whether or not
'--enable-debugging' is specified in configure cmdline, debugging
is always enabled.
We should disable ntp debugging by default.

Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>

---
--- a/configure.ac
+++ b/configure.ac
@@ -2458,7 +2458,7 @@
         [+ include ntpd debugging code]
     )],
     [ntp_ok=$enableval],
-    [ntp_ok=yes]
+    [ntp_ok=no]
 )
 case "$ntp_ok" in
  yes)