Signer crashes when hsm_create_context() failed to create context

ods-signerd: signer/rrset.c:667: rrset_sign: assertion ctx failed

There is a check on ctx early on that logs a critical error if hsm_create_context() failed. However, there is no proper handling of the error yet. Three solutions suggested:

• Stop the signer.
• Abort the drudger.
• Try again forever.

Or somewhat in the middle (and of course the most work):

• Try again for a couple of times, if still fails, abort the drudger. Let the signer engine restart any drudgers that have been aborted.