1st. Create_field does not have function vers_sys_field() kind of handy
function, second I think Create_field and Field should not divert much , and
Field does have this function.

2nd. Versioning column does not have NOT_NULL_FLAG, since they can never be
null. So I have added NOT_NULL_FLAG.

3rd. Since I added NOT_NULL_FLAG this created one issue , versioning column
of datatype bigint unsigned were getting NO_DEFAULT_VALUE_FLAG. This makes
test like versioning.insert to fail, Reason being If a column gets this
flag if we insert 'default' value it will generate error(that is why ) test
was failing. So now versioning column wont get NO_DEFAULT_VALUE_FLAG flag.