-Correct problem where a return value was not being checked resulting in xCATd potentially crashing on startup

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@4298 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/lib/xcat/plugins/AAsn.pm

@@ -294,7 +294,7 @@ sub mountInstall
     my $nomount = 0;
 
     my $retdata = xCAT::Utils->readSNInfo($nodename);
-    if ($retdata->{'arch'})
+    if (ref $retdata and $retdata->{'arch'})
     {                               # no error
         $master = $retdata->{'master'};    # management node
         $os     = $retdata->{'os'};