Removed "hard" exception in ProcessorMgr::processRunHeader()

[rete]

BEGINRELEASENOTES

• remove exception thrown in ProcessorMgr::processRunHeader() if gear detector name is different from the one in the lcio file, and just warn the user

ENDRELEASENOTES

[rete]

The current implementation of ddsim writes a run header at end of lcio file, instead of at the beginning of the file. This exception in ProcessorMgr is thrown at end of processing of our current reconstruction. The production is actually processing simulation files with a detector name that is different from the reconstructed one (e.g ILD_l4_v02 for simulation and ILD_l4_o1_v02 for reconstruction). If ddsim fix this problem of run header written at end of file, the reconstruction will not work anymore without this PR.