Fix gem source warning message.
Fix gem source warning message.

The source :rubygems is deprecated because HTTP requests are insecure.
Please change your source to 'https://rubygems.org' if possible, or
'http://rubygems.org' if not.

doghrim/fpm,schatt/fpm,jerizm/fpm,virtkick/fpm,vi4m/fpm,djhaskin987/merge-demo,djhaskin987/merge-demo,fetep/fpm,schatt/fpm,cturra/fpm,jerizm/fpm,linearregression/fpm,snailwalker/fpm,vi4m/fpm,hlawrenz/fpm,joseph-onsip/fpm,paul-krohn/fpm,doghrim/fpm,snailwalker/fpm,josephfrazier/fpm,doghrim/fpm,mzaccari/fpm,gearmover/fpm,virtkick/fpm,Tapjoy/fpm,schatt/fpm,dischord01/fpm,wyaeld/fpm,elvido/fpm,tjyang/fpm,fetep/fpm,paul-krohn/fpm,gearmover/fpm,elvido/fpm,hlawrenz/fpm,tjyang/fpm,linearregression/fpm,jerizm/fpm,mildred/fpm,pskrz/fpm,fetep/fpm,vi4m/fpm,josephfrazier/fpm,hlawrenz/fpm,josephfrazier/fpm,mildred/fpm,rbramwell/fpm,josephfrazier/fpm,dischord01/fpm,wyaeld/fpm,wyaeld/fpm,Tapjoy/fpm,gearmover/fpm,hlawrenz/fpm,mildred/fpm,rbramwell/fpm,dischord01/fpm,schatt/fpm,elvido/fpm,tjyang/fpm,mzaccari/fpm,rbramwell/fpm,dischord01/fpm,cturra/fpm,sideci-sample/sideci-sample-fpm,Tapjoy/fpm,pskrz/fpm,sideci-sample/sideci-sample-fpm,tjyang/fpm,linearregression/fpm,mildred/fpm,paul-krohn/fpm,wyaeld/fpm,godp1301/fpm,virtkick/fpm,mzaccari/fpm,vi4m/fpm,sideci-sample/sideci-sample-fpm,fetep/fpm,pskrz/fpm,godp1301/fpm,paul-krohn/fpm,rbramwell/fpm,joseph-onsip/fpm,joseph-onsip/fpm,mzaccari/fpm,jerizm/fpm,gearmover/fpm,linearregression/fpm,djhaskin987/merge-demo,joseph-onsip/fpm,doghrim/fpm,snailwalker/fpm,virtkick/fpm,godp1301/fpm,elvido/fpm,Tapjoy/fpm,snailwalker/fpm,cturra/fpm,godp1301/fpm,cturra/fpm,pskrz/fpm