hyperv/kvp_daemon: Make poll(2) block indefinitely

Submitted by:	Jun Su <junsu microsoft com>
Reviewed by:	Dexuan Cui <decui microsoft com>, me, adrain
Approved by:	adrian
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D4762

contrib/hyperv/tools/hv_kvp_daemon.c

@@ -1437,7 +1437,7 @@ main(int argc, char *argv[])
 
 
 	for (;;) {
-		r = poll (hv_kvp_poll_fd, 1, 100);
+		r = poll (hv_kvp_poll_fd, 1, INFTIM);
 
 		KVP_LOG(LOG_DEBUG, "poll returned r = %d, revent = 0x%x\n",
 		    r, hv_kvp_poll_fd[0].revents);