[Fix] `nvm_die_on_prefix`: avoid grepping env functions in bash
[Fix] `nvm_die_on_prefix`: avoid grepping env functions in bash

ironically, nvm itself has functions that matched this grep.

PeterDaveHello/nvm,creationix/nvm,ljharb/nvm,ljharb/nvm,creationix/nvm,PeterDaveHello/nvm