Check_MK Werk 3139: fixed a couple of minor issues in call to notification scripts

ID: 3139 Title: fixed a couple of minor issues in call to notification scripts Component: Notifications Level: 1 Class: Bug Fix Version: 1.2.9i1 The fixed issues are as follows: - in case of a timeout of the notification script, the script is supposed to be terminated. This worked only on python 2.6 and newer - due to timing there was a good chance the exit code of the notification script was ignored - the output of the notification script was buffered in memory until the process exited before being written. Theoretically this could cause high memory usage in the notification processes