Move journal-api into filesystems.tmpl as a Chapter.  Applies on top of the
previous docbook: make a filesystems book patch.

Remove trailing whitespace from journal-api chapter.  Align some of the
tags.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>