Add check for git to install script.
Add check for git to install script.

cjac/nvm,reybango/nvm,chinazhaghai/nvm,michael-ni/nvm,reybango/nvm,mirydz/nvm,wskplho/nvm,pmq20/nvm,hanhailong/nvm,bbuck/nvm,wahyutaufik/nvm,jaawerth/nvm,icyflame/nvm,devedbox/nvm,pmq20/nvm,youleiy/nvm,xtuple/nvm,Richardphp/nvm,cjac/nvm,wahyutaufik/nvm,ljharb/nvm,joneit/nvm,JanChw/nvm,jbergstroem/nvm,lukechilds/nvm,bevacqua/nvm,ljharb/nvm,kumaria/nvm,PeterDaveHelloKitchen/nvm,thomasf/nvm,vinaykaradia/clone-nvm,jbergstroem/nvm,woss/nvm,wskplho/nvm,evocateur/nvm,chinazhaghai/nvm,dfackler/nvm,slariviere/nvm,slariviere/nvm,DigitallySeamless/nvm,diegofcb10/nvm,IonicaBizauKitchen/nvm,scq000/nvm,Ingelheim/nvm,fnogatz/swivm,kumaria/nvm,christophercaburog/nvm,nontage24/nvm,woss/nvm,parasaro92/nvm,elrasguno/nvm,CristianCantoro/nvm,creationix/nvm,icyflame/nvm,christophercaburog/nvm,edwmurph/nvm,misterdjules/nvm,Kuzirashi/nvm,kmctown/nvm,Theodeus/nvm,modulexcite/nvm,PeterDaveHelloKitchen/nvm,edwmurph/nvm,hkdobrev/nvm,elrasguno/nvm,lukechilds/nvm,nontage24/nvm,williamboman/nvm,vinaykaradia/clone-nvm,mmorejon/nvm,NicCollins/nvm,tlevine/nvm,psychoss/nvm,thomasf/nvm,SampleLiao/nvm,greyhwndz/nvm,sjfkai/nvm,dfackler/nvm,evocateur/nvm,cirosantilli/nvm,joneit/nvm,greyhwndz/nvm,bevacqua/nvm,parasaro92/nvm,WY08271/nvm,cirosantilli/nvm,tlevine/nvm,JasonChrYoung/nvm,domenicosolazzo/nvm,tianzhihen/nvm,gtdeng/nvm,JasonChrYoung/nvm,IonicaBizauKitchen/nvm,modulexcite/nvm,hanhailong/nvm,gtdeng/nvm,creationix/nvm,jhliberty/nvm,Salahudeen/nvm,WY08271/nvm,bbuck/nvm,misterdjules/nvm,Theodeus/nvm,LeeLovCY/nvm,diegofcb10/nvm,Kuzirashi/nvm,appleboy/nvm,egilkh/nvm,Richardphp/nvm,SampleLiao/nvm,scq000/nvm,cnpm/nvm,DigitallySeamless/nvm,PeterDaveHello/nvm,mmorejon/nvm,youleiy/nvm,michael-ni/nvm,jhliberty/nvm,owen-it/nvm,cnpm/nvm,tianzhihen/nvm,williamboman/nvm,Salahudeen/nvm,psychoss/nvm,mirydz/nvm,jaawerth/nvm,owen-it/nvm,egilkh/nvm,Ingelheim/nvm,devedbox/nvm,PeterDaveHello/nvm,CristianCantoro/nvm,hkdobrev/nvm,LeeLovCY/nvm,JanChw/nvm,kmctown/nvm,domenicosolazzo/nvm