Hardening/harness fixes

### Description
- Fixed the 'apparently without reason' failing harness tests (removed calls to accumulatorStop)
- Added flock around all writes in logMsg.cpp (unfortunately without fixing the problem in notification_different_sizes.test)
- Removed the 'xml/XML' for xmllint in harnessFunctions.sh.
- Fixed a FIXME, using curlIt instead of just 'curl' (this adds HTTP headers)