Fix nova.tests.test_nova_rootwrap on Fedora 17.
Fix nova.tests.test_nova_rootwrap on Fedora 17.

Fix bug 992916

This patch resolves a unit test failure on Fedora 17.  The root cause is
that 'sleep' is '/usr/bin/sleep' instead of '/bin/sleep'.  Update the
test to allow that.

Change-Id: I5c8e04baec7159a8c10c9beb96cff58fd383e71c

n0ano/ganttclient