Without warning, a JIRA v8.6.0 server fails while synchronising an LDAP directory with the following error:

• "Unable to find the username of the principal."

The error message does not tell us the username, nor does the error message tell us the principal, and so makes life unnecessarily difficult for admins.

Acceptance Criteria:

• Add the username (or the criteria being used to find the username) to the error message.
• Add the principal (or the criteria being used to find the principal) to the error message.

2020-07-17 14:12:43,132+0200 Caesium-1-3 INFO ServiceRunner [c.a.crowd.directory.DbCachingRemoteDirectory] FULL synchronisation for directory [ 10000 ] starting
2020-07-17 14:12:43,208+0200 Caesium-1-3 ERROR ServiceRunner [c.a.c.d.l.mapper.entity.LDAPUserAttributesMapper] The following record does not have a username: NameAwareAttribute; attributes:

{sn=NameAwareAttribute; id: sn; hasValuesAsNames: false; orderMatters: false; values: [Template], nsuniqueid=NameAwareAttribute; id: nsUniqueId; hasValuesAsNames: false; orderMatters: false; values: [022efe81-76d411ea-a1b6ce9f-216b1919]}

2020-07-17 14:12:43,210+0200 Caesium-1-3 INFO ServiceRunner [c.a.crowd.directory.DbCachingRemoteDirectory] failed synchronisation complete for directory [ 10000 ] in [ 78ms ]
2020-07-17 14:12:43,290+0200 Caesium-1-3 ERROR ServiceRunner [c.atlassian.scheduler.JobRunnerResponse] Unable to synchronise directory
com.atlassian.crowd.exception.OperationFailedException: org.springframework.ldap.UncategorizedLdapException: Unable to find the username of the principal.