Fix if statements in bump.sh
Fix if statements in bump.sh

[#160069129](https://www.pivotaltracker.com/story/show/160069129)

Co-authored-by: Danny Berger <8efccf38e9d8f361e1973ad644e1b1e50ad8ecfe@pivotal.io>

bosh-packages/golang-release,bosh-packages/golang-release