psql: Fix invalid memory access

Due to an apparent thinko, when printing a table in expanded mode
(\x), space would be allocated for 1 slot plus 1 byte per line,
instead of 1 slot per line plus 1 slot for the NULL terminator.  When
the line count is small, reading or writing the terminator would
therefore access memory beyond what was allocated.

src/bin/psql/print.c

@@ -1210,8 +1210,8 @@ print_aligned_vertical(const printTableContent *cont, FILE *fout)
 	 * We now have all the information we need to setup the formatting
 	 * structures
 	 */
-	dlineptr = pg_local_malloc((sizeof(*dlineptr) + 1) * dheight);
-	hlineptr = pg_local_malloc((sizeof(*hlineptr) + 1) * hheight);
+	dlineptr = pg_local_malloc((sizeof(*dlineptr)) * (dheight + 1));
+	hlineptr = pg_local_malloc((sizeof(*hlineptr)) * (hheight + 1));
 
 	dlineptr->ptr = pg_local_malloc(dformatsize);
 	hlineptr->ptr = pg_local_malloc(hformatsize);