ctdb-tests: Stop cat command failure from causing test failure

ctdb-tests: Stop cat command failure from causing test failure

In certain circumstance, which aren't obvious, cat(1) can fail when
attempting to write a lot of data.  This is due to something (probably
write(2)) returning EAGAIN.

Given that the -v option should only really be used for test
debugging, ignore the failure instead of spending time debugging it.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14446
Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>