CHAR/VARCHAR do not include prefix, VAR/BINARY has a lenght
All TStrings have charset and collation
merge nathanlws: Tweak i_s.columns {max,octet}_length for (var){char,binary}

Merge pull request #1088 from nathanlws/sql-layer/tweak-length-is-columns
https://github.com/FoundationDB/sql-layer/pull/1088