Checkmk Werk 7908: Improve metric plugin compatibility

ID: 7908 Title: Improve metric plugin compatibility Component: Multisite Level: 1 Class: Bug fix Version: 1.7.0i1 GUI metric plugins which were built for Checkmk 1.5 or older could access the variable MAX_CORES and the function indexed_color(). This was not possible in previous 1.6 releases which made these plugins incompatible. Both names are available again for plugins in the path <tt>local/share/check_mk/web/plugins/metrics/</tt>.