This changes the fsfilt transaction calculations to take into account the

This changes the fsfilt transaction calculations to take into account the
cases where we are updating multiple log files for a single transaction
(esp. unlink of files).  For small numbers of stripes this isn't very
likely to cause problems, but after updating to the new log format for 2306,
we happened to run single-file IORs with 32 stripes as the first IO to the
filesystem, and this caused 32 new logs to be created in a single transaction
when that file was unlinked.  This caused the unlink journal transaction to
repeatedly run out of credits and BUG the MDS until this patch was applied.

Removed fsfilt_extN.c since it is perpetually out-of-date and any time it
needs to be used it is easier to just run fsfilt_ext3.c through sed.
b=2059, b=2931