BUG: Fix formatting error in exception message
BUG: Fix formatting error in exception message

This commit fixes a simple formatting error in the
generation of an exception message. The message
is supposed to contain the expected vs. the actual
dtype, but instead contained two times the expected
dtype.

madphysicist/numpy,numpy/numpy,madphysicist/numpy,mhvk/numpy,endolith/numpy,pizzathief/numpy,simongibbons/numpy,mhvk/numpy,mattip/numpy,jakirkham/numpy,jakirkham/numpy,WarrenWeckesser/numpy,pizzathief/numpy,jorisvandenbossche/numpy,seberg/numpy,mattip/numpy,pdebuyl/numpy,jakirkham/numpy,endolith/numpy,endolith/numpy,rgommers/numpy,ahaldane/numpy,pizzathief/numpy,numpy/numpy,endolith/numpy,jorisvandenbossche/numpy,ahaldane/numpy,ahaldane/numpy,grlee77/numpy,pbrod/numpy,charris/numpy,grlee77/numpy,numpy/numpy,WarrenWeckesser/numpy,seberg/numpy,anntzer/numpy,mattip/numpy,jorisvandenbossche/numpy,simongibbons/numpy,grlee77/numpy,numpy/numpy,pbrod/numpy,charris/numpy,simongibbons/numpy,MSeifert04/numpy,simongibbons/numpy,jorisvandenbossche/numpy,charris/numpy,abalkin/numpy,seberg/numpy,ahaldane/numpy,pdebuyl/numpy,grlee77/numpy,charris/numpy,anntzer/numpy,mhvk/numpy,pizzathief/numpy,MSeifert04/numpy,jorisvandenbossche/numpy,abalkin/numpy,mhvk/numpy,MSeifert04/numpy,simongibbons/numpy,pbrod/numpy,WarrenWeckesser/numpy,grlee77/numpy,rgommers/numpy,jakirkham/numpy,MSeifert04/numpy,pbrod/numpy,seberg/numpy,pbrod/numpy,mattip/numpy,WarrenWeckesser/numpy,anntzer/numpy,pizzathief/numpy,madphysicist/numpy,anntzer/numpy,ahaldane/numpy,WarrenWeckesser/numpy,MSeifert04/numpy,pdebuyl/numpy,abalkin/numpy,jakirkham/numpy,madphysicist/numpy,rgommers/numpy,pdebuyl/numpy,madphysicist/numpy,mhvk/numpy,rgommers/numpy