[monitoring-plugins] check_dns: fix error detection on sles nslookup

[Sven Nierlein]

 Module: monitoring-plugins
 Branch: master
 Commit: 9daeceaed39b04e79ba364e311e0532e4fdf711f
 Author: Sven Nierlein <sven at nierlein.de>
   Date: Sun Mar 12 21:02:58 2017 +0100
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=9daecea

check_dns: fix error detection on sles nslookup

on sles (ex. 11sp1) systems the nslookup output for not found was not parsed correctly
and interpreted as ok when it should be critical:

./check_dns -H nosuchhost.nodomain -t 1 -vvv
/usr/bin/nslookup -sil nosuchhost.nodomain Server:         10.0.2.3
Address:        10.0.2.3#53
Non-authoritative answer:
*** Can't find nosuchhost.nodomain: No answer
DNS OK: 0.011 seconds response time. nosuchhost.nodomain returns |time=0.010892s;;;0.000000

Signed-off-by: Sven Nierlein <sven at nierlein.de>

---

 plugins/check_dns.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/plugins/check_dns.c b/plugins/check_dns.c
index 5feafc8..f206163 100644
--- a/plugins/check_dns.c
+++ b/plugins/check_dns.c
@@ -360,6 +360,7 @@ error_scan (char *input_buffer)
   /* Host or domain name does not exist */
   else if (strstr (input_buffer, "Non-existent") ||
            strstr (input_buffer, "** server can't find") ||
+           strstr (input_buffer, "** Can't find") ||
      strstr (input_buffer,"NXDOMAIN"))
     die (STATE_CRITICAL, _("Domain %s was not found by the server\n"), query_address);