Don't lose comment content if it failed to create

Hello,

This is a really minor change whose object is to avoid losing a possibly long comment just because the server rejected it.
Common reasons for rejections include ill-formed e-mail address and ill-formed website URL.

For now, I am not adding an error message to let the user know that there was an error but that is something I can add if we discuss it first.

Additionally, this pull request solves partly my concern in #131