Revision 1804553

On the '1.3.x-fix-outgoing-request-err' branch: Tweak the error handling
code when reading the data to write to the connection so that it would
immediately propagate all real errors.

With r1804543 in place, such errors should be propagated anyway, as a
"real error" would prevent the detect_eof() from being called, but this
change should make the code a bit more future-proof.

Note: in trunk, the new serf_pump__write() function does the same thing.

* outgoing.c
  (write_to_connection): Unconditionally return real errors from
   serf_bucket_read_iovec().