klippy_connection: log raw peercred data on error

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/klippy_connection.py

@@ -233,13 +233,16 @@ class KlippyConnection:
                 "Unable to get Unix Socket, cant fetch peer credentials"
             )
             return
+        data: bytes = b""
         try:
             data = sock.getsockopt(socket.SOL_SOCKET, socket.SO_PEERCRED, 12)
             pid, uid, gid = struct.unpack("@LLL", data)
         except asyncio.CancelledError:
             raise
         except Exception:
-            logging.exception("Failed to get Klippy Credentials")
+            logging.exception(
+                f"Failed to get Klippy Peer Credentials, raw: 0x{data.hex()}"
+            )
             return
         self._peer_cred = {
             "process_id": pid,