Fixed bug where showcfg for non-existing config files died silently

Made servername verification talk directly to the nameserver, not just any server.

dnsupdate.py

@@ -130,7 +130,9 @@ def readcfg(msg, show=""):
       return msg
   else:
     if not os.path.exists(msg['cfgfile']):
-      msg['error'].append("No such file: %s" % msg['cfgfile'])
+      if show:
+        checkerror(msg, show="errors")
+      msg['error'].append("No such file; '%s'" % msg['cfgfile'])
       return msg
     cfgfile = open(msg['cfgfile'], 'r')
 
@@ -229,7 +231,9 @@ def verify_ip(msg):
   ip = ""
   host = msg['hostname'] + "." + msg['domain']
   try:
-    ans = dns.resolver.query(host, 'A')
+    res = dns.resolver.Resolver()
+    res.nameservers = [msg['nameserver']]
+    ans = res.query(host)
     for res in ans:
       ip = res.to_text()
   except dns.exception.Timeout: