ccan: make tal_dump() format more regular.

Putting a \n in there was a pain: I had to do:

awk '/CHILDREN/ { SAVED=$0 } !/CHILDREN/ { print SAVED$0; SAVED="" }' < lightningd-tal_dump > lightningd-tal_dump-children-on-same-line

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>