HttpRequest: put cookies in a single header entry

* Http spec says headers can be split when they are comma separated
 * However, cookies are semicolon separated, so it is not acceptable to
split them.
 * We will want to implement some way to limit the cookie header entry
size, as servers have a limit on what they can accept (usually around 4K
characters). The RFC also says we don't need to remember more than 20
cookies per domain.

src/kits/network/libnetapi/HttpRequest.cpp

@@ -871,11 +871,17 @@ BHttpRequest::_AddHeaders()
 	// Context cookies
 	if (fOptSetCookies && (fContext != NULL)) {
 		BNetworkCookie* cookie;
+		BString cookieString;
 
 		for (BNetworkCookieJar::UrlIterator it
 				= fContext->GetCookieJar().GetUrlIterator(fUrl);
-				(cookie = it.Next()) != NULL;)
-			fOutputHeaders.AddHeader("Cookie", cookie->RawCookie(false));
+				(cookie = it.Next()) != NULL;) {
+			cookieString << cookie->RawCookie(false);
+			cookieString << "; ";
+		}
+
+		if (cookieString.length() > 0)
+			fOutputHeaders.AddHeader("Cookie", cookieString);
 	}
 
 	// Write output headers to output stream