Re: [PATCH] doc: clarify tutorial error section

["Davide \"FunkyAss\" Del Zompo" <davide.delzompo@xxxxxxxxx>]

First of all, I just realized that you may need a bit of context: I'm sorry, I'm
pretty new to contributing.

The "Handling the errors" section in the first chapter of the Tutorial states
that calling ssh_get_error() and ssh_get_error_code() with NULL as argument is
fine. Looking at the source code, that will make the library segfault,
derefencing NULL.

The patch rephrases the paragraph, clarifying how to use said functions.