Increase curl timeout to two minutes
Increase curl timeout to two minutes

In #165, a few users are getting time outs.

```
  Compiling Ruby
 !
    ERROR: Command: 'set -o pipefail; curl --fail --retry 3 --retry-delay 1 --connect-timeout 3 --max-time 20 https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/ruby-1.9.3-jruby-1.7.3.tgz -s -o - | tar zxf -' failed unexpectedly:
    ERROR: 
    ERROR: gzip: stdin: invalid compressed data--format violated
    ERROR: tar: Unexpected EOF in archive
    ERROR: tar: Unexpected EOF in archive
    ERROR: tar: Error is not recoverable: exiting now
 !
```
pietrop/heroku-buildpack-ruby,orenyk/heroku-buildpack-ruby,gls1/heroku-buildpack-ruby-pdftk,rvizza/heroku-buildpack-gsl-ruby,diasks2/heroku-buildpack-mecab,crdschurch/heroku-buildpack-ruby,pkgr/heroku-buildpack-ruby,CPPWind/ruby-buildpack,leonardykris/mos-ruby-buildpack,Git-Host/prelang-buildpack,jgable/buildpack-ruby-rack-setup-tasks,trumaker/heroku-buildpack-turbo-sprockets,cloudn/buildpack-ruby,qnyp/heroku-buildpack-ruby-bower,dtao/deft-buildpack-ruby,takii/db2rubybuildpack,iamjarvo/ruby-buildpack,jonasoberschweiber/heroku-buildpack-ruby,sstelfox/buildpack-ruby,recursecenter/heroku-buildpack-ruby,crdschurch/heroku-buildpack-ruby,cordata/heroku-buildpack-ruby,hpcloud/ruby-buildpack,Jonty/ruby-buildpack,takii/db2rubybuildpack,jumptvs/BP_Ruby,iamjarvo/ruby-buildpack,jayshreeanand/heroku-buildpack-ruby,recursecenter/heroku-buildpack-ruby,jumptvs/BP_Ruby,heroku/heroku-buildpack-ruby,hpcloud/ruby-buildpack,icelab/heroku-buildpack-ruby,space150/heroku-buildpack-ruby,jumptvs/BP_Ruby,bwaite-jaroop/heroku-buildpack-ruby,CPPWind/ruby-buildpack,ablease/custom-buildpack,fcruxen/ruby-buildpack,simonnordberg/heroku-buildpack-ruby,jgable/buildpack-ruby-rack-setup-tasks,hatofmonkeys/ruby-testing-buildpack,michaelphines/alexa-nest,Micka33/heroku-buildpack-ruby-liblua,sky-uk/ruby-buildpack,amaltson/heroku-buildpack-ruby,teodor-pripoae/heroku-buildpack-ruby,hatofmonkeys/ruby-testing-buildpack,bskyb-commerce/help-heroku-buildpack,ascot21/heroku-buildpack-turbo-sprockets,wakermahmud/heroku-buildpack-jekyll,d-reinhold/cf-buildpack-ruby,ibmdb/db2rubybuildpack,Altoros/ruby-buildpack,qnyp/heroku-buildpack-ruby-bower,mattmanning/heroku-buildpack-ruby-jekyll,blueapron/heroku-buildpack-ruby,allomov/fat-free-heroku-buildpack-ruby,lyoshenka/heroku-buildpack-ruby-jekyll,beydogan/ruby-buildpack,ltrademark/heroku-buildpack-ruby,jayshreeanand/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,jumptvs/BP_Ruby,d-reinhold/cf-buildpack-ruby,erintherad/heroku-buildpack-ruby,orlando/heroku-buildpack-ruby,ChefSteps/heroku-buildpack-ruby,cloudn/buildpack-ruby,DouglasAllen/heroku-buildpack-ruby,mintybit/heroku-buildpack-ruby,cloudfoundry/ruby-buildpack,barakav/heroku-buildpack-ruby,tenjikinc/heroku-buildpack-ruby,aarongray/heroku-buildpack-ruby,cloudfoundry/ruby-buildpack,pietrop/heroku-buildpack-ruby,amaltson/heroku-buildpack-ruby,ilpoldo/heroku-buildpack-ruby,rowanoulton/heroku-buildpack-ruby,codykrieger/heroku-buildpack-jekyll,icelab/heroku-buildpack-ruby,tdenovan/heroku-buildpack-ruby,stolt45/heroku-buildpack-ruby-with-sqlite3,iamjarvo/ruby-buildpack,cmaggard/heroku-buildpack-turbo-sprockets,shuber/heroku-buildpack-ruby,takii/heroku-buildpack-ruby,tomwolfe/heroku-buildpack-gsl-ruby,Dim25/heroku-buildpack-ruby-GSL,CPPWind/ruby-buildpack,Git-Host/prelang-buildpack,ericroberts/heroku-buildpack-ruby,DigitalInnovation/heroku-buildpack-mslabs,schu/heroku-buildpack-ruby,swipesense/heroku-buildpack-ruby,brightbytes/heroku-buildpack-ruby-without-assets-precompile,stolt45/heroku-buildpack-ruby-with-sqlite3,mperejda/heroku-buildpack-ruby,Nedomas/heroku-buildpack-ruby-minus-node-with-node-paths,ltrademark/heroku-buildpack-ruby,Jonty/ruby-buildpack,michaelphines/alexa-nest,d-reinhold/cf-buildpack-ruby,gls1/heroku-buildpack-ruby-pdftk-new,HYPERHYPER/heroku-buildpack-ruby,fgbreel/heroku-buildpack-ruby,schu/buildpack-testing,reesio/heroku-buildpack-ruby,rowanoulton/heroku-buildpack-ruby,trumaker/heroku-buildpack-turbo-sprockets,bskyb-commerce/ruby-buildpack,cloudfoundry/ruby-buildpack,qstream/heroku-buildpack-ruby,moneyadviceservice/heroku-buildpack-ruby-bowndler,cloudControl/buildpack-ruby,ablease/custom-buildpack,jonasoberschweiber/heroku-buildpack-ruby,fcruxen/ruby-buildpack,pilotcreative/heroku-buildpack-ruby,rvizza/heroku-buildpack-gsl-ruby,gbenedict/heroku-buildpack-ruby,mrhenry/heroku-buildpack-ruby,scottatron/moc-buildpack,gls1/heroku-buildpack-ruby-pdftk-new,ericboehs/heroku-buildpack-ruby,hellojustin/heroku-buildpack-custom-ruby,Nedomas/heroku-buildpack-ruby-minus-node-with-node-paths,takii/heroku-buildpack-ruby,Altoros/ruby-buildpack,fcruxen/ruby-buildpack,andycroll/heroku-buildpack-jekyll,ruby/heroku-buildpack-www-ruby-lang,bwaite-jaroop/heroku-buildpack-ruby,ndbroadbent/heroku-buildpack-turbo-sprockets,ascot21/heroku-buildpack-turbo-sprockets,tpope/heroku-buildpack-ruby-tpope,swipesense/heroku-buildpack-ruby,samfrench/heroku-buildpack-ruby,hpcloud/ruby-buildpack,jonseaberg/heroku-buildpack-turbo-sprockets,tpope/heroku-buildpack-ruby-tpope,Micka33/heroku-buildpack-ruby-liblua,sky-uk/ruby-buildpack,fgbreel/heroku-buildpack-ruby,cloudfoundry/ruby-buildpack,Jonty/ruby-buildpack,markaschneider/heroku-buildpack-ruby-ffmpeg-sox,zunda/heroku-buildpack-ruby,pilotcreative/heroku-buildpack-ruby,DouglasAllen/heroku-buildpack-ruby,0x00evil/heroku-buildpack-ruby,ablease/custom-buildpack,qstream/heroku-buildpack-ruby,fcruxen/ruby-buildpack,allomov/fat-free-heroku-buildpack-ruby,ChefSteps/heroku-buildpack-ruby,cloudControl/buildpack-ruby,CPPWind/ruby-buildpack,Scalingo/ruby-buildpack,barakav/heroku-buildpack-ruby,ablease/custom-buildpack,anay/buildpack-ruby-with-oracle-jdk,mattwalters/heroku-buildpack-ruby,erintherad/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,KoanHealth/heroku-buildpack-marvin-setup,bskyb-commerce/ruby-buildpack,scottatron/moc-buildpack,stefansundin/heroku-buildpack-ruby,bellycard/heroku-buildpack-ruby,mattmanning/heroku-buildpack-ruby-jekyll,gls1/heroku-buildpack-ruby-pdftk,Altoros/ruby-buildpack,Dim25/heroku-buildpack-ruby-GSL,Jonty/ruby-buildpack,ndbroadbent/heroku-buildpack-turbo-sprockets,hatofmonkeys/ruby-testing-buildpack,hellojustin/heroku-buildpack-custom-ruby,ericboehs/heroku-buildpack-ruby,andycroll/heroku-buildpack-jekyll,dtao/teeny-buildpack,sky-uk/help-heroku-buildpack,gbenedict/heroku-buildpack-ruby,tenjikinc/heroku-buildpack-ruby,daltonrenaldo/heroku-buildpack-ruby,cordata/heroku-buildpack-ruby,zoomer/heroku-buildpack-ruby-bower,takii/db2rubybuildpack,jonseaberg/heroku-buildpack-turbo-sprockets,takii/db2rubybuildpack,lyoshenka/heroku-buildpack-ruby-jekyll,DyegoCosta/heroku-buildpack-ruby,guidance-guarantee-programme/heroku-buildpack-princexml-old,codykrieger/heroku-buildpack-jekyll,diasks2/heroku-buildpack-mecab,brightbytes/heroku-buildpack-ruby-without-assets-precompile,bellycard/heroku-buildpack-ruby,iamjarvo/ruby-buildpack,dleavitt/heroku-buildpack-ruby,righi/instacart-heroku-buildpack,zidekmat/buildpack-ruby,mrhenry/heroku-buildpack-ruby,ekaranto/rails4-bluemix-buildpack,catalyzeio/buildpack-ruby,DyegoCosta/heroku-buildpack-ruby,zidekmat/buildpack-ruby,cloudn/buildpack-ruby,dtao/teeny-buildpack,engineyard/heroku-buildpack-ruby,electricobjects/heroku-buildpack-ruby,musicglue/heroku-buildpack-ruby,packetmonkey/heroku-buildpack-ruby,DigitalInnovation/heroku-buildpack-mslabs,orenyk/heroku-buildpack-ruby,ekaranto/rails4-bluemix-buildpack,hixi/heroku-buildpack-ruby,anay/buildpack-ruby-with-oracle-jdk,stefansundin/heroku-buildpack-ruby,dlorson/gentle-buildpack,hixi/heroku-buildpack-ruby,reesio/heroku-buildpack-ruby,ilpoldo/heroku-buildpack-ruby,catalyzeio/buildpack-ruby,dleavitt/heroku-buildpack-ruby,cmaggard/heroku-buildpack-turbo-sprockets,ekaranto/rails4-bluemix-buildpack,guidance-guarantee-programme/heroku-buildpack-princexml-old,makifund/heroku-buildpack-ruby,Altoros/ruby-buildpack,awebneck/heroku-buildpack-canvas,sky-uk/ruby-buildpack,blueapron/heroku-buildpack-ruby,ibmdb/db2rubybuildpack,HYPERHYPER/heroku-buildpack-ruby,dlorson/gentle-buildpack,bskyb-commerce/ruby-buildpack,tomwolfe/heroku-buildpack-gsl-ruby,hpcloud/ruby-buildpack,space150/heroku-buildpack-ruby,shuber/heroku-buildpack-ruby,cloudn/buildpack-ruby,sky-uk/help-heroku-buildpack,0x00evil/heroku-buildpack-ruby,aarongray/heroku-buildpack-ruby,simonnordberg/heroku-buildpack-ruby,heroku/heroku-buildpack-ruby,vhx/heroku-buildpack,redhotvengeance/heroku-buildpack-deep-thought,jasonlevens/heroku-buildpack-ruby,righi/instacart-heroku-buildpack,pkgr/heroku-buildpack-ruby,beydogan/ruby-buildpack,Genius/heroku-buildpack-ruby,schu/buildpack-testing,ericroberts/heroku-buildpack-ruby,daltonrenaldo/heroku-buildpack-ruby,moneyadviceservice/heroku-buildpack-ruby-bowndler,sstelfox/buildpack-ruby,mintybit/heroku-buildpack-ruby,electricobjects/heroku-buildpack-ruby,leonardykris/mos-ruby-buildpack,Genius/heroku-buildpack-ruby,dtao/deft-buildpack-ruby,zunda/heroku-buildpack-ruby,sky-uk/ruby-buildpack,dieze/heroku-buildpack-ruby-hooks,mattwalters/heroku-buildpack-ruby,dieze/heroku-buildpack-ruby-hooks,donnykurnia/heroku-buildpack-ruby,jasonlevens/heroku-buildpack-ruby,bskyb-commerce/help-heroku-buildpack,ekaranto/rails4-bluemix-buildpack,engineyard/heroku-buildpack-ruby,derrek/heroku-buildpack-ruby,bskyb-commerce/ruby-buildpack,ibmdb/db2rubybuildpack,KoanHealth/heroku-buildpack-marvin-setup,teodor-pripoae/heroku-buildpack-ruby,redhotvengeance/heroku-buildpack-deep-thought,cloudfoundry/ruby-buildpack,tdenovan/heroku-buildpack-ruby,zoomer/heroku-buildpack-ruby-bower,markaschneider/heroku-buildpack-ruby-ffmpeg-sox,derrek/heroku-buildpack-ruby,wakermahmud/heroku-buildpack-jekyll,packetmonkey/heroku-buildpack-ruby,awebneck/heroku-buildpack-canvas,makifund/heroku-buildpack-ruby,orlando/heroku-buildpack-ruby,schu/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,Scalingo/ruby-buildpack,musicglue/heroku-buildpack-ruby,vhx/heroku-buildpack,mperejda/heroku-buildpack-ruby,samfrench/heroku-buildpack-ruby