Bounty #459 - Fix 

https://assembly.com/coderwall/bounties/459

Before, the TeamsController would set `@job_page` to true if there was anything in `params[:job_id]`. This caused problems because if a job id that didn't actually match anything in the database, the template would still try to call methods on `@job` even though it was nil. 

This PR changes it so that `@job_page` is based on whether or not a job was found and loaded, rather than just the presence of `show_params[:job_id]`