Fix server error when submitting on non-existent project

[Pansysk75]

Previously, if a submission happened on a non-existent project, the CheckForTooManyBuilds() would result in a 500 http code, which caused me some confusion.

Thanks!

[williamjallen]

Simply relocating the check is not a robust fix. Instead, it would be better to check the return value of $this->project->FindByName($projectname); and use $this->failProcessing() to return an appropriate error if the project does not exist.

[Pansysk75]

Simply relocating the check is not a robust fix. Instead, it would be better to check the return value of $this->project->FindByName($projectname); and use $this->failProcessing() to return an appropriate error if the project does not exist.

That makes sense, thank you for the feedback! I made the requested changes. Please feel free to take the wheel, as I'm not too experienced with either the CDash codebase or php.

[williamjallen]

Hi @Pansysk75, thanks for this contribution. I rebased your PR and pushed some minor changes, and will merge once CI passes.