quilt-tester: Increase wait time after detecting containers starting
quilt-tester: Increase wait time after detecting containers starting

With the move to Jenkins, a timing issue caused network tests to fail.
It was discovered that these errors were resolved when the test was
ran again at a later time, so the tester has been modified to wait
a little bit longer before running tests on a set of containers.

kklin/quilt,NetSys/quilt,kayousterhout/quilt,quilt/quilt,kklin/kelda,LuiseV/quilt,kklin/quilt,LuiseV/quilt,quilt/quilt,kayousterhout/quilt,ejj/quilt-dev,quilt/quilt,kayousterhout/quilt,NetSys/quilt,kelda/kelda,kelda/kelda,LuiseV/quilt,ejj/quilt-dev,kelda/kelda,NetSys/quilt,ejj/quilt-dev,kayousterhout/quilt,kklin/kelda,kklin/quilt,ejj/quilt-dev,kklin/kelda,quilt/quilt,NetSys/quilt,NetSys/quilt,kelda/kelda,kklin/quilt,LuiseV/quilt,LuiseV/quilt,kklin/kelda