Prevent renaming of jobs or warn admins not to rename jobs, and avoid non-ascii or uppercase characters

[alberto56]

When you rename a job in jenkins, the /path/to/the/workspace changes as well, and the old workspace remains in existence. This causes several problems:

(1) Because /var/lib/jenkins/conf.d/oldjob.conf still links to the old workspace, the address mysite.jenkins, which simpletest uses for internal tests, still links to the old workspace. Furthermore, because the old workspace still exists, if you actually load mysite.jenkins, you will see your site (so you might think everything is working fine -- which is misleading)
(2) Your new /path/to/workspace does NOT contain a settings.php file. This is problematic because someone might try to create one but forget to add the $base_url parameter, and even if the $base_url parameter is added, it will still lead to the old workspace (see (1), above)
(3) In some cases a project might be renamed to an identical string but with different casing. for exemple "project" might be renamed "Project" or "PROJECT". This will actually create a new directory where only the casing is different. This might lead to confusion in some cases.

PROPOSED SOLUTIONS

• Ideally your team might want to adopt a policy for naming projects (example: no more than 8 characters (for use on wall displays), all lower-case, no special characters, etc.
• You might want to warn your team never to rename projects (unless they are ready to debug everything, which is equivalent to creating a new project)
• With more advanced permission matrix, https://wiki.jenkins-ci.org/display/JENKINS/Request+Rename+Or+Delete+Plugin might be added.