It is natural to write "abc" in place of ["set",["abc"]] and vice versa.
I cannot think of a reason not to support this, and it can make reading
and writing OVSDB files and transactions easier, so support it.
A "min" value greater than 1 is problematic for the database. There is no
reasonable way to synthesize a default value for such a column: keys in a
set or map must unique, so the database cannot, say, simply set a set of
3 or more integers to [0, 0, 0].
This should have no effect on the vswitch in practice because it does not
have any columns that require more than one element.
