Handling HLT Virtual seeds: API level

Dear All

as raised in https://its.cern.ch/jira/browse/CMSLITOPS-329 L1CE is throwing up a spurious error because the HLT menu contains a "virtual" l1 seed which the HLT catches and interprets as to accept any L1 seed: L1GlobalDecision. This is not in the L1 menu thus L1CE throws an error. This needs to be fixed.

This the api only solution as discussed in that JIRA which checks HLT seeds against known virtual seeds as well as the seeds in the L1 menu. It is meant to propose a possible solution but is not intended to be merged, for one it is not tested as I do not know your testing setup. And feel free to impliment your own solution of this.