Now FILE transfers send headers to the header callback like HTTP and
other protocols. Also made curl_easy_getinfo(...CURLINFO_PROTOCOL...)
work for FILE in the callbacks.
Makes "curl -i file://.." and "curl -I file://.." work like before
again. Applied the bold header logic to them too.
Regression from c1c2762 (7.61.0)
Reported-by: Shaun Jackman
Fixes#3083Closes#3101
after 7.16.2. This is much due to the different treatment file:// gets
internally, but now I added test 231 to make it less likely to happen again
without us noticing!
