Use strider_server_name instead of SERVER_NAME for hostname.

[alexfernandez]

Solves issue #55 (comment). The problem is that Strider is changing the env variable SERVER_NAME to strider_server_name here.

[knownasilya]

Strider uses the values from rc, which parses the envs as 'strider_*' and we use the parsed value here: https://github.com/Strider-CD/strider/blob/e29f0f0466ec1dcbde60460e3d4159096ca61a5c/lib/libconfig.js#L68

[alexfernandez]

You are right, it is working now even without this PR. Closing.

[knownasilya]

I know it's complicated. Once I have time I plan on refactoring the config system to make it less convoluted and easier for first time users.

[alexfernandez]

No problem. Thanks for your lightning quick support!