obsolete: properly drop 'date' from metadata...
obsolete: properly drop 'date' from metadata
Mistakes were made while resolving rebase conflicts in 4bc96685a40c. This led to
'date' being preserved in metadata when reading markers from a binary stream.
As a result, some known markers were seen as "new" when pulling. I noticed it
because a no-op pulls from main added about 600 duplicated markers to my
obsstore (for each pull).
I do not believe we need to perform any specific action to actively
de-duplicates existing obsstore. After this fix, duplicated markers will no be
propagated and the few affected repositories can probably deal with duplication (or
people can repull the obsstore from a clone).
As a side effect, we decode metadata only once, reducing the impact of the hack
in fm0 to store extra important data (parents and date).
