tdb: don't free old recovery area when expanding if already at EOF.

tdb: don't free old recovery area when expanding if already at EOF.

We allocate a new recovery area by expanding the file.  But if the
recovery area is already at the end of file (as shown in at least one
client case), we can simply expand the record, rather than freeing it
and creating a new one.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Autobuild-User: Rusty Russell <rusty@rustcorp.com.au>
Autobuild-Date: Wed Dec 21 06:25:40 CET 2011 on sn-devel-104