Add logging to RenewCrypto

Add logging to RenewCrypto

As the LURenewCrypto is a pain to debug, this patch
adds a lot more logging of events to the method.
Note:
- As renew-crypto is a relatively rarely used operation
  in a normal production cluster, this won't clutter up
  real user's log files.
- Most of the messages are in debug mode, so they would
  anyway just show up in log files of clusters run in
  debug mode (as for example our QA clusters.
- A few log messages are in error mode, which is
  intentional as they log more details about the errors
  than is given in the feedback functions.

Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>