[Fix] `nvm install -s`: properly precompute clang version
[Fix] `nvm install -s`: properly precompute clang version

PeterDaveHelloKitchen/nvm,creationix/nvm,PeterDaveHello/nvm,edwmurph/nvm,PeterDaveHelloKitchen/nvm,edwmurph/nvm,PeterDaveHello/nvm,evocateur/nvm,ljharb/nvm,creationix/nvm,ljharb/nvm,evocateur/nvm