Remove double transaction warning from rasdaman

[Dimitar Misev]

Due to some legacy reasons, rasdaman opens a double transaction to postgres, which leads to warnings and potentially other issues. This is not valid anymore in the current versions of postgres, so it should be removed from rasdaman.

[miracee]

• Set up a test system and debugged for the PostgreSQL warning.
• The warning won't occur in debug mode.
• Figured out that rasdaman is doing a proper job here.
• All open transactions will be closed.
• The PostgreSQL warning just is confusing.
• That the warning shows up in log as long as you won't enable features for debugging is a PostgreSQL issue not a rasdaman issue.

[abeccati]

It looks like we can lower priority and schedule this to the "future" milestone unless there is a quick solution in sight for it or we have hints on the potential other issues.

[Dimitar Misev]

I think this can actually be closed? There is nothing to be done in rasdaman about it.