fixed bug in macros.catalyze regarding sites
fixed bug in macros.catalyze regarding sites

We were using e_site with product instead of s_site. Since all our models used
the same site 'bf' for e_site and s_site this went unnoticed for a while.

alubbock/pysb-legacy,d-fan/pysb,jmuhlich/pysb,LoLab-VU/pysb,d-fan/pysb,spgarbet/pysb,pysb/pysb,alubbock/pysb,neurord/pysb,d-fan/pysb,neurord/pysb,spgarbet/pysb,spgarbet/pysb,alubbock/pysb-legacy,LoLab-VU/pysb,johnbachman/pysb,alubbock/pysb-legacy,johnbachman/pysb,alubbock/pysb-legacy,neurord/pysb