[Rivet] Error (typo) in MC_IDENTIFIED

[Ivan Razumov]

Dear Rivet developers,

there is a minor yet annoying bug in MC_IDENTIFIED analysis: the 
analysis itself writes object with 'MC_IDENTIFIED' path, but the 
corresponding .plot file lists these objects under 'MC_GENERIC' path.
This prevents tools that use .plot file (e.g. rivet-cmphistos) from 
adding correct title/axes labels to the object.

Thanks,
Ivan