fixed issue with set-fields not applying db delimiters

I had an issue where, using a mysql database, not all of my column names were having the delimiters applied correct.

My query looked similar to this:

(update client (set-fields {:joindate somedate}) (where {:id id}))

I found the id field was handled correctly i.e. was translated to `id`, but the joindate field was not. It ended up being translated to "joindate" (which is not valid in mysql), rather than `joindate`