Use write_all() instead of write()

write() is allowed to write only partial data. Good luck debugging why
some part of the log message is missing. This commit changes the logging
to use write_all() instead, which ensures everything is written.

This might end up doing multiple writes to /dev/kmsg, which would turn
into multiple log records. I think that is still better than silently
discarding some data.

Signed-off-by: Uli Schlachter <psychon@znc.in>

src/utils.rs

@@ -41,7 +41,7 @@ pub fn log_impl(msg: Arguments<'_>) {
     match OpenOptions::new().write(true).open("/dev/kmsg") {
         Ok(mut file) => {
             msg.push('\n');
-            file.write(msg.as_bytes()).ok();
+            file.write_all(msg.as_bytes()).ok();
         }
         Err(_) => {
             println!(