incorrect parsing of timestamp offset for time zones with non integer offset

[ehrt74]

Hi!

in connection.go 499 it is assumed that the time zone offset of vertica is an integer number of hours. for time zones like india (+530) this code fails. attempts after that to read a timestamp from the database fail because the appended time zone information is incomplete.

a fix would be something like:

func getTimeZoneOffset(str string) string {
    for i := len(str) - 1; i >= 0 && i >= len(str)-8; i-- {
	ch := str[i]
	if ch == '+' || ch == '-' {
		return str[i:]
	}
    }
    return "+00"
}

many thanks!