Support tables that have columns named desc

[rafael]

Desc

• Tables with columns name 'desc' are not being parsed correctly. This adds a fix similar to the one in here:Fixes regression in parser #4172 to support such tables.

[slanning]

This seems to cause conflicts:

...
$ goyacc -o go/vt/sqlparser/sql.{go,y}

conflicts: 235 reduce/reduce
$ git checkout go/vt/sqlparser/sql.go
$ git bisect bad
698aa3721d6d23c824f6835969f811384ba6d04f is the first bad commit
...

[rafael]

@sougou - Do you know what might be happening here? I do not recall seeing that error when generating sql.go, but also seeing it if I try to recompile the parser.