Fix return types of responses to view requests
This fixes an issue that was introduced with 72258e2 and e5b1aee.
Background:
Although all things still seemed to work, each request to a view
generated an exception with the following stack trace:
```
exception error: undefined function vacc:get/2
in function chttpd:result/2 (src/chttpd.erl, line 297)
in call from chttpd:handle_request_int/1 (src/chttpd.erl, line 276)
in call from mochiweb_http:headers/6 (src/mochiweb_http.erl, line 122)
```
2 files changed
