There were a few reports that upgrading Ubuntu recently caused issues
because we assert that the sqlite3 library version matches the one we
were built with. 'make' doesn't fix this, because it doesn't know the
external libraries have changed.
Fix this harder, with a helper which updates a file every binary depends
on, which gets relinked every time so we detect link changes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>