Fix last offset output using skip in od(1)

Yeah, if the skipping is longer than the file itself, we need
to take the skip value, not the address.
Also, only print the last newline when we've actually printed
at least 1 address.

od.c

@@ -89,10 +89,10 @@ od(FILE *in, char *in_name, FILE *out, char *out_name)
 		if (feof(in) || ferror(in) || ferror(out))
 			break;
 	}
-	if (addr)
+	if (addr - skip > 0)
 		fputc('\n', out);
 	if (radix != 'n') {
-		printaddress(out, addr);
+		printaddress(out, MAX(addr, skip));
 		fputc('\n', out);
 	}
 }