cosmetic: clarify language in vty read error

This is very minor but it annoys every time I see it.
The text: "Error occurred during reading below line:"
is not a complete sentence. The default understanding
in english having left out the article implies
that the error occured reading below [the] specified line, not
that the error occured reading [the] specified line.

That is to say, The message implied that the printed line
was the last successfully parsed line.

Change-Id: Ib4dd135feb9609b14983db5dac321a70267d8f30
diff --git a/src/vty/vty.c b/src/vty/vty.c
index 644d4ed..113a781 100644
--- a/src/vty/vty.c
+++ b/src/vty/vty.c
@@ -1481,7 +1481,7 @@
 			fprintf(stderr, "There is no such command.\n");
 			break;
 		}
-		fprintf(stderr, "Error occurred during reading below "
+		fprintf(stderr, "Error occurred during reading the below "
 			"line:\n%s\n", vty->buf);
 		vty_close(vty);
 		return -EINVAL;