deb: fix bug in find_dsc_file

src/context/ssh.rs

@@ -244,6 +244,15 @@ impl ContextDriver for SshDriver {
         remote_file.write_all(content.as_bytes())?;
         Ok(())
     }
+
+    fn exists(&self, path: &Path) -> io::Result<bool> {
+        let sess = connect_ssh(&self.host, self.user.as_deref(), self.port)?;
+        let sftp = sess.sftp().map_err(io::Error::other)?;
+        match sftp.stat(path) {
+            Ok(_) => Ok(true),
+            Err(_) => Ok(false),
+        }
+    }
 }
 
 impl SshDriver {