Use cache directory when downloading composer.phar
Use cache directory when downloading composer.phar

Since there is a cache dir there is no need to populate the project
directory with temp files. Plus the permissions on the project dir
might not allow that.

mothership-ec/composer,jreinke/composer,fh/composer,shipci/composer,szeber/composer,jtanjung/composer,staabm/composer,ammmze/composer,mauricionr/composer,Netmisa/composer,melvis01/composer,Nicofuma/composer,fabpot/composer,rednut/composer,andrewnicols/composer,composer/composer,PatidarWeb/composer,gencer/composer,zhaoyan158567/composer,Ocramius/composer,webberwu/composer,joshdifabio/composer,kuczek/composer,00F100/composer,aitboudad/composer,jmleroux/composer,kidaa/composer,bd808/composer,curry684/composer,cgvarela/composer,vdm-io/composer,oligriffiths/composer,floverdevel/composer,stefangr/composer,guillaumelecerf/composer,sroze/composer,fabiang/composer,remicollet/composer,balbuf/composer,zgj12306/composer,naderman/composer,johnstevenson/composer,erasys/composer,alcohol/composer,druid628/composer,barkinet/composer,slopjong/posedoc,olvlvl/composer,Teino1978-Corp/Teino1978-Corp-composer,localheinz/composer,cs278/composer,mikicaivosevic/composer,hirak/composer,slbmeh/composer,brighten01/composer,JeroenDeDauw/composer,nicolas-grekas/composer,nater1067/composer,supriyantomaftuh/composer,1234-/composer,GodLesZ/composer,pierredup/composer,thetaxman/composer,kocsismate/composer,yaman-jain/composer,mrmark/composer,dzuelke/composer,nevvermind/composer,samdark/composer,mickaelandrieu/composer,blacksun/composer,till/composer,phansys/composer,DiceHoldingsInc/composer,flaupretre/composer,myPublicGit/composer,yched/composer,Flyingmana/composer,SpacePossum/composer,milleruk/composer,ryanaslett/composer,davidolrik/composer,universalsoftware/composer,theiven70/composer,AndBicScadMedia/composer,cesarmarinhorj/composer,stof/composer,legoktm/composer,JeckoHeroOrg/composer,oxygen-cms/composer,andrerom/composer,javihgil/composer,gsdevme/composer,Soullivaneuh/composer,yinhe007/composer,iamluc/composer,Danack/composer,MoT3rror/composer,ncusoho/composer,Seldaek/composer,Jericho25/composer,Zagorakiss/composer,marcuschia/composer,dymissy/composer,JBleijenberg/composer,Risyandi/composer