Revert "Support tables that have columns named desc"

[rafael]

@sougou - it seems like the easy fix that we use for #4172, does not work here because desc is also in the reserved_keyword. I missed this comment:

/*
  These are not all necessarily reserved in MySQL, but some are.

  These are more importantly reserved because they may conflict with our grammar.
  If you want to move one that is not reserved in MySQL (i.e. ESCAPE) to the
  non_reserved_keywords, you'll need to deal with any conflicts.

  Sorted alphabetically
*/

I'm reverting this change for now, not sure right now how to solve the conflicts in the grammar.

Signed-off-by: Rafael Chacon rafael@slack-corp.com