Merge branch 'ms/http-no-more-failonerror'

Debugging help for http transport. * ms/http-no-more-failonerror: test: test GIT_CURL_VERBOSE=1 shows an error remote-curl: unset CURLOPT_FAILONERROR remote-curl: define struct for CURLOPT_WRITEFUNCTION http: enable keep_error for HTTP requests http: support file handles for HTTP_KEEP_ERROR