- remove reference to _exc_info before reraise to reduce cycles
- remove reference to _exc_info before reraise to reduce cycles

robin900/sqlalchemy,brianv0/sqlalchemy,zzzeek/sqlalchemy,bdupharm/sqlalchemy,j5int/sqlalchemy,alex/sqlalchemy,olemis/sqlalchemy,wfxiang08/sqlalchemy,EvaSDK/sqlalchemy,davidfraser/sqlalchemy,EvaSDK/sqlalchemy,brianv0/sqlalchemy,epa/sqlalchemy,hsum/sqlalchemy,epa/sqlalchemy,WinterNis/sqlalchemy,ThiefMaster/sqlalchemy,pdufour/sqlalchemy,hsum/sqlalchemy,elelianghh/sqlalchemy,inspirehep/sqlalchemy,alex/sqlalchemy,elelianghh/sqlalchemy,ThiefMaster/sqlalchemy,halfcrazy/sqlalchemy,Cito/sqlalchemy,bootandy/sqlalchemy,276361270/sqlalchemy,Cito/sqlalchemy,monetate/sqlalchemy,davidjb/sqlalchemy,sandan/sqlalchemy,pdufour/sqlalchemy,dstufft/sqlalchemy,bdupharm/sqlalchemy,wfxiang08/sqlalchemy,276361270/sqlalchemy,Akrog/sqlalchemy,itkovian/sqlalchemy,wujuguang/sqlalchemy,bootandy/sqlalchemy,wujuguang/sqlalchemy,graingert/sqlalchemy,sqlalchemy/sqlalchemy,graingert/sqlalchemy,davidfraser/sqlalchemy,WinterNis/sqlalchemy,robin900/sqlalchemy,monetate/sqlalchemy,Akrog/sqlalchemy,halfcrazy/sqlalchemy,olemis/sqlalchemy,itkovian/sqlalchemy,sandan/sqlalchemy,alex/sqlalchemy,dstufft/sqlalchemy,inspirehep/sqlalchemy,Cito/sqlalchemy,davidjb/sqlalchemy,j5int/sqlalchemy