Bash script returns failure if the sdk is already installed

[bekir-ozturk]

Before #233, if the script detected that the version to be installed was already installed, it would return success before exiting. After the changes, the script considers this a failure and returns 1. This is causing problems with users that are relying on the return values.

• Update the bash script so that finding an existing installation results in success code (0) being returned.