fix #3038: check user before renewing ticket

Fixes a bug in which the userid of the ticket cache is updated,
when a user connects, but the ticket itself is not.
This means a newly connected user has a previously connected
user's ticket and thus, cannot do anything, as the client will
attempt to use the invalid ticket.

e.g. if john@pbs connected to the server first, followed by
mike@pbs, the following would be stored in the ticket cache.

{
  "localhost": {
    "mike@pbs": {
      "ticket": "PBS:john@pbs:AAAA",
      "timestamp": 1601039326,
      "token": "BBBB"
    }
  }
}

Signed-off-by: Dylan Whyte <d.whyte@proxmox.com>

src/client/http_client.rs

@@ -219,7 +219,8 @@ fn store_ticket_info(prefix: &str, server: &str, username: &str, ticket: &str, t
 
     let empty = serde_json::map::Map::new();
     for (server, info) in data.as_object().unwrap_or(&empty) {
-        for (_user, uinfo) in info.as_object().unwrap_or(&empty) {
+        for (user, uinfo) in info.as_object().unwrap_or(&empty) {
+            if user == username {
                 if let Some(timestamp) = uinfo["timestamp"].as_i64() {
                     let age = now - timestamp;
                     if age < ticket_lifetime {
@@ -228,6 +229,7 @@ fn store_ticket_info(prefix: &str, server: &str, username: &str, ticket: &str, t
                 }
             }
         }
+    }
 
     replace_file(path, new_data.to_string().as_bytes(), CreateOptions::new().perm(mode))?;