[TYPO3-core] FYI: #????: in ajax.php same error message is used twice for different errors

[Martin Kutschker]

Hi!

Problem: two kind of errors ("no function configured" and "function does
not exist") generate the same error message making the stuff a bit
harder to debug than necessary.

Solution: Use different messages.

I consider this as a no-brainer (and a bug) and have committed this to
trunk and TYPO3_4-2.

Masi