Correctly use user_id instead of launchpad_id

Previously launchpad_id was set for all records, but we already
have primary key 'user_id' that should be used instead.
When merging two profiles it is possible that there are 2 known
launchpad ids or gerrit ids for the same user. Now processor writes
info-level message for such profiles

Change-Id: I27580578b10272a2e1b7e998025db523b4075a18
Merge "Correctly use user_id instead of launchpad_id"