Title: Fix crashing Nagios core in rare case when excessive commands are being executed
Level: 2
Component: livestatus
Class: fix
Compatible: compat
State: unknown
Version: 1.2.7i3
Date: 1441283031

The crash was due to the fact that the internal Nagios API for executing commands
is not thread safe. The CMC was not affected. This fixes the problems:

http://tracker.nagios.org/view.php?id=656

http://lists.mathias-kettner.de/pipermail/checkmk-en/2015-February/014497.html

Thanks to Ryan C. Underwood for the patch!
