fix some xcsv bugs. (#477)

fix some xcsv bugs. (#477)

These led to non-sensical motoactv files in test-all.  These
non-sensical files lead to the discovery of a holux write passed
end of buffer bug.

1. fea062ee7 writtime expects a strftime format specification.
When writing XT_TIMET_TIME_MS with writtime the strpftime format
specification ("%s") that was previously used was replaced by a printf
format specification ("%ld").  Thus the twelve hour clock followed by
a 'd' character was printed instead of the number of seconds since the Epoch.

2. 172073cdb When intending to print the field encloser the record
delimiter printed instead.