Title: winperf_msx_queues: fixed crash when winperf data is missing
Level: 1
Component: checks
Class: fix
Compatible: compat
State: unknown
Version: 1.2.7i3
Date: 1441287640

Previously the windows agent would return empty sections if it couldn't retrieve performance data.
The winperf_msx_queues check responded to this empty section by crashing.
This has been fixed by making sure the agent doesn't return empty winperf sections and by making the
check handle empty sections gracefully
