Revert "PR#2944: decode protonmsg props field when loading from db"
    
    This reverts commit 34d1c8eb9e17491e819153ce1e482691aaac1da4, reversing
    changes made to fdccd38148666d07ab2fc09c33681b466323c743.
    
    Proper solution was part of https://pagure.io/koji/pull-request/2955, so
    this merge was a mistake. Reverting.