fetch(3): plug some leaks

In the successful case, sockshost is not freed prior to return.

The failure case can now be hit after fetch_reopen(), which was not true
before. Thus, we need to make sure to clean up all of the conn resources
which will also close sd. For all of the points prior to fetch_reopen(), we
continue to just close sd.

CID: 1419598, 1419616