Fix attachment rename processing in upgrade_2-1_mysql.sql
Fix attachment rename processing in upgrade_2-1_mysql.sql

Signed-off-by: Noteworthy Software, Inc <2dbc2fd2358e1ea1b7a6bc08ea647b9a337ac92d@noteworthysoftware.com>

margarett/SMF2.1,MustafaCan/SMF2.1,mkress/SMF2.1,MustafaCan/SMF2.1,georaldc/SMF2.1,georaldc/SMF2.1,StealthWombat/SMF2.1-more-forkery,margarett/SMF2.1,mkress/SMF2.1,mkress/SMF2.1,StealthWombat/SMF2.1-more-forkery