remove extra newline from perror() calls

perror error adds a newline, so don't split error message
across two lines.
diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index d1c6620..6dc61eb 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -317,7 +317,7 @@
 static int flush_update(void)
 {
 	if (rtnl_send(&rth, filter.flushb, filter.flushp) < 0) {
-		perror("Failed to send flush request\n");
+		perror("Failed to send flush request");
 		return -1;
 	}
 	filter.flushp = 0;