ok, after looking a little, it looks like openfire creates a random pasword for the openfire@localhost user it sets up on first run and/or empty database schema, then it stores it someplace.
you can do:
mysql> SHOW GRANTS FOR 'openfire'@'localhost';
and it will list all the permissions. the only problem, the password is a hash of the original, so you wont be able to exactly re-create this user without the original password.
you can try having openfire create a brand new database by importing the schema fresh per the doc: http://www.igniterealtime.org/builds/openfire/docs/latest/documentation/database .html
and then re-run the openfire first start configuration - follow this thread: http://community.igniterealtime.org/thread/33825
then, after openfire has set things back up, you can try deleting the newly created openfire database and then import your mysqldump file which will re-create the openfire database.
it's a long shot, but perhaps the newly setup mysql user will retain permissions of the imported database.