imsg.h does not need sys/tree.h.

ok eric

src/usr.sbin/ntpd/imsg.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: imsg.h,v 1.4 2009/09/15 10:54:59 jacekm Exp $	*/
+/*	$OpenBSD: imsg.h,v 1.5 2010/04/27 21:04:04 nicm Exp $	*/
 
 /*
  * Copyright (c) 2006, 2007 Pierre-Yves Ritschard <pyr@openbsd.org>
@@ -18,8 +18,6 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include <sys/tree.h>
-
 #define READ_BUF_SIZE		65535
 #define IMSG_HEADER_SIZE	sizeof(struct imsg_hdr)
 #define MAX_IMSGSIZE		16384