`http_dl->bytes_received` was already free'd when it was accessed inside
`aesgcm_file_get()`.
Change `http_file_get()` to optionally return the number of bytes received
so we know how much data we have to decrypt.
This fixes#1994
Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>
Fixes https://github.com/profanity-im/profanity/issues/1794
Explanation
The problem is the download's identifier. Downloads are given an ID so they can be referenced later when their progress changes. Currently, the download's ID is the download's URL. When you download the same file twice, you have two downloads with the same ID. Download progress updates are shown on the first of both downloads with the same ID.
Solution
Change the download's ID from its URL to a random number. A random ID is generated when get_random_string() is called from cmd_funcs.c. Several other functions are updated to cope with the new ID format.
