-Correct warning about unitialized value in ipmi plugin

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@1943 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

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

@@ -4335,7 +4335,7 @@ sub domsg {
 		#local $SIG{ALRM} = sub { $timedout = 1 and die };
 		#alarm($timeout);
 		my $received = $s->can_read($timeout);
-		if($received > 0) {
+		if($received and $received > 0) {
 			if ($sock->recv($recv,128)) {
 				if($recv) {
 					@response = unpack("C*",$recv);