libexec/rbenv-version: get rid of misleading "set by $(rbenv-version-origin)" message when system ruby is in use
libexec/rbenv-version: get rid of misleading "set by $(rbenv-version-origin)" message when system ruby is in use

sstephenson/rbenv,rbenv/rbenv,jasonkarns/rbenv,sstephenson/rbenv,rbenv/rbenv,jasonkarns/rbenv,jasonkarns/rbenv,sstephenson/rbenv