rkt: Document the function in config test
rkt: Document the function in config test

It might be a bit unclear why this function exists when there is
ioutil.TempFile.

It is mostly about getting a file with desired suffix.

Yhgenomics/rkt,rkt/rkt,kinvolk/rkt,sstabellini/rkt,achanda/rkt,endocode/rkt,nhlfr/rkt,ybubnov/rkt,s-urbaniak/rkt,michelangelo13/rkt,achanda/rkt,shtouff/rkt,krnowak/rkt,mattthias/pkg-rkt,matthaias/rkt,smarvin/rkt,dalanlan/rkt,sinfomicien/rkt,maquanyi/rkt,rhvgoyal/rkt,bsmr-go/rkt,shobhit85/rkt,linki/rkt,lucasallan/rkt,blixtra/rkt,MattDees/rkt,lucasallan/rkt,dgonyeo/rkt,chrisseto/rkt,iaguis/rkt,yifan-gu/rkt,monstermunchkin/rkt,sgotti/rkt,il9ue/rkt,lee212/rkt,ChengTiesheng/rkt,maquanyi/rkt,squaremo/rkt,liugenping/rkt,ChengTiesheng/rkt,bsmr-go/rkt,fdserr/rkt,ybubnov/rkt,liubq919/rkt,squeed/rkt,jonboulle/rkt,tixxdz/rkt,jasonchaffee/rkt,lucasallan/rkt,sinfomicien/rkt,iaguis/rkt,Shashwatsh/rkt,wparad/rkt,clearlinux/rkt,MabinGo/rkt,endocode/rkt,tv42/rkt,euank/rkt,liubq919/rkt,matthaias/rkt,s-urbaniak/rkt,mjg59/rkt,cab105/rkt,yifan-gu/rocket,jjlakis/rkt,xnox/rkt,rot26/rkt,mjg59/rkt,intelsdi-x/rkt,Shashwatsh/rkt,smarvin/rkt,tixxdz/rkt,jjlakis/rkt,rkt/rkt,tixxdz/rkt,tv42/rkt,klizhentas/rkt,markllama/rkt,lee212/rkt,Wilybald/rkt,jzelinskie/rkt,Wilybald/rkt,alexhersh/rkt,Shashwatsh/rkt,rot26/rkt,sinfomicien/rkt,wparad/rkt,cab105/rkt,blixtra/rkt,liugenping/rkt,nhlfr/rkt,joshix/rkt,s-urbaniak/rkt,marineam/rkt,rhvgoyal/rkt,clearlinux/rkt,matthaias/rkt,yifan-gu/rocket,mike1729/rkt,alban/rkt,akshaykarle/rkt,crawford/rkt,MattDees/rkt,iankronquist/rkt,fdserr/rkt,linki/rkt,sgotti/rkt,maquanyi/rkt,clearlinux/rkt,jakon89/rkt,jakon89/rkt,coreos/rkt,euank/rkt,shobhit85/rkt,mike1729/rkt,crawford/rkt,adfernandes/rkt,jonboulle/rkt,rkt/rkt,marineam/rkt,squaremo/rkt,luebken/rkt,sstabellini/rkt,tmrts/rkt,MabinGo/rkt,krnowak/rkt,coreos/rkt,klizhentas/rkt,jakon89/rkt,chrisseto/rkt,xnox/rkt,luebken/rkt,markllama/rkt,monstermunchkin/rkt,mattthias/pkg-rkt,shtouff/rkt,krnowak/rkt,blixtra/rkt,euank/rkt,ybubnov/rkt,squeed/rkt,linki/rkt,lucasallan/rkt,kbrwn/rkt,tv42/rkt,iaguis/rkt,dalanlan/rkt,alexhersh/rkt,cab105/rkt,joshix/rkt,jjlakis/rkt,ChengTiesheng/rkt,il9ue/rkt,alexhersh/rkt,crawford/rkt,Yhgenomics/rkt,klizhentas/rkt,jasonchaffee/rkt,jzelinskie/rkt,endocode/rkt,yifan-gu/rocket,dgonyeo/rkt,Yhgenomics/rkt,michelangelo13/rkt,squeed/rkt,liubq919/rkt,kbrwn/rkt,yifan-gu/rkt,akshaykarle/rkt,kinvolk/rkt,intelsdi-x/rkt,yifan-gu/rkt,intelsdi-x/rkt,alban/rkt,nhlfr/rkt,mike1729/rkt,mattthias/pkg-rkt,markllama/rkt,smarvin/rkt,intfrr/rkt,Wilybald/rkt,achanda/rkt,fdserr/rkt,rhvgoyal/rkt,joshix/rkt,tmrts/rkt,sgotti/rkt,intfrr/rkt,adfernandes/rkt,dgonyeo/rkt,iankronquist/rkt,intfrr/rkt,liugenping/rkt,luebken/rkt,MattDees/rkt,wparad/rkt,adfernandes/rkt,jonboulle/rkt,shtouff/rkt,sstabellini/rkt,rkt/rkt,Wilybald/rkt,jzelinskie/rkt,il9ue/rkt,iankronquist/rkt,kinvolk/rkt,kinvolk/rkt,mjg59/rkt,xnox/rkt,bsmr-go/rkt,akshaykarle/rkt,rot26/rkt,chrisseto/rkt,shobhit85/rkt,kbrwn/rkt,squaremo/rkt,marineam/rkt,monstermunchkin/rkt,alban/rkt,dalanlan/rkt,coreos/rkt,jasonchaffee/rkt,MabinGo/rkt,lee212/rkt,michelangelo13/rkt,tmrts/rkt,joshix/rkt