Revert "Comment out redundant call"

This reverts commit 033df4f63d1d31ab15c24e41ce382c96c652efec.

It is not redundant. I do not know what I was thinking.
Modify attachments table at the end of checksetup.

I do not know why it didn't work in update_install_db hook and I do
not have time to find it out. I could comment out the "REFERENCES" key
in column definition then final attachements table had two stock
foreign keys (to "bugs" and "profiles" tables). Uncommenting ended up
with having only one foreign key - the one I wanted to add, stock ones
weren't created... And in this case, of course, checksetup failed with
error 121 (MySQL error code 121: Duplicate key on write or update).
Simplify index addition
Update the update routine
Simplify index addition