rados/verify: increase api tests timeout

This has been timing out for weeks to months (hard to say since before that
we were consistently hitting an OSD crash on shutdown).  The runs I've looked
at are making progress and seem fine ... just slow because of valgrind and
because of thrashing.

Backport: firefly
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 175057f3bceb50623f6bfeded3fe0b9257edea7d)