Conversion for SqlIntervalT in makeSqlValue doesn't handle intervals with days

[nomeata]

Josh reports at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=596183 against version 2.2.3.1:

When HDBC-postgresql converts a SqlIntervalT to a SqlDiffTime in
makeSqlValue, it assumes hours:minutes:seconds, splits on ':', and tries
to use "read" to parse two Integer values and a Double. However,
postgresql stores intervals internally as months, days, and seconds; the
separate days field allows for 23-hour or 25-hour days (thank you
daylight savings time). For such intervals, postgresql outputs "N mons
N days N:N:N.N", with any of the three components omitted if zero. This
causes HDBC-postgresql to fail in "read".