fix infinite loading

[ptcc]

fixes #17

[fzaninotto]

I fail to see how that fixes the issue, can you elaborate on the solution?

[ptcc]

by moving the put of FETCH_START inside the try/catch block we ensure that FETCH_CANCEL will still be dispatched if the saga is canceled after the FETCH_START put and before the response = yield call(restClient, restType, meta.resource, payload);

(and that is exactly where it gets canceled in the case described in the issue)