Title: mssql_blocked_sessions: Fixed unknown states if only one session is blocked
Level: 1
Component: checks
Class: fix
Compatible: compat
State: unknown
Version: 1.2.8p18
Date: 1486137493

The check state has been unknown if only one session was blocked, because
the checkplugin was expecting one additional first line from the agent output
which does not exist anymore. The new version can handle both cases and will
not accidentally drop any information anymore.
