Fix typo on config file location

[icp1994]

curlrc -> .curlrc

[dfandrich]

This fix looke like it matches the current behaviour, but I suspect the code is not quite right. I think it should be looking for the non-dot version of the file in the XDG_CONFIG_HOME location (which is how other programs do it), but there's explicit code in findfile.c that disables that check for some reason.

[jay]

This fix looke like it matches the current behaviour, but I suspect the code is not quite right.

See #12129. I proposed a fix in #12135 but I've softened on it. Maybe it is better to do it this way and document the way it has been working.

[bagder]

I think we should fix the code rather than to document the bug.