ddns-gargoyle: Fix gross error with if with empty body.

We also remove pesky trailing whitespaces.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
gargoyle: session_validator: Remove duplicate break from case.

We also clean some whitespace.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
gargoyle: session_validator: Vastly simplify code.

While the code is smaller, it is also branch-free, which should help with
generation of the code.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
gargoyle: session_validator: More simplification of the code.

This further reduces the memory consumption of variables on the stack and
also reduces by two the number of calls to `sprintf`.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>