Update ajax.php

Ensure acquireLock doesn't interfere with renew/release

- [ ] This modifies the ajax.php dispatcher regex, fixing the release function.
- [ ] This https://github.com/clonemeagain/osTicket-1.8/commit/30d0150b2d0bf6bc77e7afbae7185b45321ee428#commitcomment-4899636 adjusts the async to not wait
- [ ] Tested repeatedly, unloading page now works as expected, https://github.com/clonemeagain/osTicket-1.8/commit/b9a926f717e44cbcbb174ce579fa8029eb1bba9e no longer necessary.

https://github.com/osTicket/osTicket-1.8/issues/327