Large spikes for throughput metrics at beginning of job

[moebiusband73]

There are spikes with impossible high values, especially for Likwid metrics, at the start of jobs.

Solution:
A quick fix would be to filter out values that are impossibly high, especially at the stat of Jobs.
On the long term the real cause for those spikes has to be investigated.

[moebiusband73]

This issue was migrated to ClusterCockpit/cc-metric-collector#103