Remove check for `nil` on `qs`
Remove check for `nil` on `qs`

Fixed by brynary/rack-test@4a4b2c1. rack-test was turning the query
string to nil if there was no argument passed in the params. This extra
`nil` check is no longer necessary after the changes made to the
rack-test gem. Fixes issue brought up in #800.

akihiro17/rack,Eric-Guo/rack,trexnix/rack,gioele/rack,fabianrbz/rack,maclover7/rack,supzann3/rack,trexnix/rack,jackxxu/rack,shaneog/rack,nmk/rack,ngpestelos/rack,jackxxu/rack,Comcast/rack,laplaceliu/rack,akihiro17/rack,rwz/rack,wjordan/rack,maclover7/rack,deepj/rack,stepri/rack,stepri/rack,deepj/rack,eavgerinos/rack,imtayadeway/rack,liamseanbrady/rack,nmk/rack,gioele/rack,Eric-Guo/rack,arronmabrey/rack,zjsxwc/rack,imtayadeway/rack,imtayadeway/rack,akihiro17/rack,davydovanton/rack,Codeman655/rack,jackxxu/rack,rwz/rack,deepj/rack,gfvcastro/rack,liamseanbrady/rack,eavgerinos/rack,maclover7/rack,shaneog/rack,Comcast/rack,eins78/rack,laplaceliu/rack,Eric-Guo/rack,wildjcrt/rack,gfvcastro/rack,keithduncan/rack,Codeman655/rack,davydovanton/rack,nmk/rack,wjordan/rack,gfvcastro/rack,davidcelis/rack,davydovanton/rack,keepcosmos/rack,rwz/rack,ngpestelos/rack,supzann3/rack,wjordan/rack,ganmacs/rack,shaneog/rack,jeremyf/rack,tylergannon/rack,arronmabrey/rack,davidcelis/rack,AMekss/rack,eins78/rack,AMekss/rack,ngpestelos/rack,davidcelis/rack,ganmacs/rack,stepri/rack,keepcosmos/rack,jeremyf/rack,eins78/rack,wildjcrt/rack,keithduncan/rack,wildjcrt/rack,tylergannon/rack,jeremyf/rack,Comcast/rack,keithduncan/rack,keepcosmos/rack,fabianrbz/rack,zjsxwc/rack,tylergannon/rack,Codeman655/rack,laplaceliu/rack,eavgerinos/rack,fabianrbz/rack,trexnix/rack,supzann3/rack,arronmabrey/rack,ganmacs/rack,AMekss/rack,gioele/rack,liamseanbrady/rack,zjsxwc/rack