curl: fix integer variable typechecks with curl_easy_setopt()

As discussed in the previous commit, we should be passing long integers, not regular ones, to curl_easy_setopt(), and compiling against curl 8.14 loudly complains if we don't. That patch fixed integer constants by adding an "L". This one deals with actual variables. Arguably these variables could just be declared as "long" in the first place. But it's actually kind of awkward due to other code which uses them: - port is conceptually a short, and we even call htons() on it (though weirdly it is defined as a regular int). - ssl_verify is conceptually a bool, and we assign to it from git_config_bool(). So I think we could probably switch these out for longs without hurting anything, but it just feels a bit weird. Doubly so because if you don't set USE_CURL_FOR_IMAP_SEND set, then the current types are fine! So let's just cast these to longs in the curl calls, which makes what's going on obvious. There aren't that many spots to modify (and as you can see from the context, we already have some similar casts). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>