bugfix: use default auth DB in mongo log reader

[rachedbenmustapha]

The mongodb log reader included /local in its connection string. The path element in mongodb's connection URI is actually the DB authenticate against, not the DB to work on. This lead to authentication failures even though roles, users, passwords etc were correct.

[bert-e]

Hello rachedbenmustapha,

My role is to assist you with the merge of this
pull request. Please type @bert-e help to get information
on this process, or consult the user documentation.

Status report is not available.

[bert-e]

Waiting for approval

The following approvals are needed before I can proceed with the merge:

• the author

• 2 peers

Peer approvals must include at least 1 approval from the following list:

• @rahulreddy

• @bennettbuchanan

• @rachedbenmustapha

[rachedbenmustapha]

@bert-e approve

[bert-e]

In the queue

The changeset has received all authorizations and has been added to the
relevant queue(s). The queue(s) will be merged in the target development
branch(es) as soon as builds have passed.

The changeset will be merged in:

• ✔️ development/8.1

The following branches will NOT be impacted:

• development/6.4
• development/7.4
• development/7.6
• stabilization/7.4.5

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[bert-e]

I have successfully merged the changeset of this pull request
into targetted development branches:

• ✔️ development/8.1

The following branches have NOT changed:

• development/6.4
• development/7.4
• development/7.6
• stabilization/7.4.5

Please check the status of the associated issue ZENKO-2215.

Goodbye rachedbenmustapha.