Update Travis build to Packer 0.7.1, so the Parallels desktop builds pass.
Update Travis build to Packer 0.7.1, so the Parallels desktop builds pass.

patcon/bento,davidalger/bento,techmaniack/bento,risdenk/bento,jhoblitt/bento,osuosl/bento,tas50/bento,loadsys/packer-builds,William-Yeh/bento,ConSol/bento,dthtvwls/bento,techmaniack/bento,runsystem-hiennt2/bento,vincentaubert/bento,0x90/bento,leohmoraes/bento,tas50/bento,RallySoftware-cookbooks/bento,b1-systems/bento,117111302/bento,stumped2/packer,mkristiansen/bento,chef/bento,bgandon/bento,orpiske/bento,josephholsten/bento,pingworks/bento,mtnsat/bento,lwieske/bento,0x90/bento,v1k0d3n/bento,orpiske/bento,lwieske/bento,davidalger/bento,lwieske/bento,Sauraus/bento,someara/bento,legal90/bento,b1-systems/bento,dthtvwls/bento,devopxteam/bento,pingworks/bento,Sauraus/bento,devopxteam/bento,Oefenweb/bento,grdryn/bento,sporting-news/bento,runsystem-hiennt2/bento,techmaniack/bento,sporting-news/bento,jhoblitt/bento,thinktainer/bento,loadsys/packer-builds,sillvan/bento,erikj/bento,patcon/bento,117111302/bento,bgandon/bento,ConSol/bento,patrickmcclory/bento,dmlb2000/bento,leejones/bento,mkristiansen/bento,vincentaubert/bento,thinktainer/bento,mtnsat/bento,devopxteam/bento,geoHeil/packerPuphetPuppet,chef/bento,legal90/bento,norcams/bento,grdryn/bento,erikj/bento,brianm/baseboxes,mmckinst/bento,ConSol/bento,someara/bento,leohmoraes/bento,dmlb2000/bento,v1k0d3n/bento,josephholsten/bento,legal90/bento,geoHeil/packerPuphetPuppet,loadsys/packer-builds,juliandunn/bento,juliandunn/bento,sillvan/bento,tas50/bento,juliandunn/bento,devopxteam/bento,Oefenweb/bento,leejones/bento,norcams/bento,mmckinst/bento,patrickmcclory/bento,risdenk/bento,RallySoftware-cookbooks/bento,osuosl/bento,norcams/bento,chef/bento,vincentaubert/bento,brianm/baseboxes,stumped2/packer,William-Yeh/bento