Make `nvm_ensure_version_installed` slightly more efficient.
Make `nvm_ensure_version_installed` slightly more efficient.

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