Removing column from gameobject_template (mangos.sql)

The gameobject_template.castBarCaption column is no longer in classicDB, it still being in the mangos.sql creates an error message on server startup when following Installation-Instructions, saying there are 34 columns expected. Removing the castBarCaption column fixed this.

Compare to:
https://github.com/classicdb/database/blob/classic/Full_DB/ClassicDB_1_4_1_z2525.sql
Lines 514330 - 514366