Don't put gem_bin_path in packages if there's no need.
Don't put gem_bin_path in packages if there's no need.

This should fix #612.

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