Fix test failure in TopologyManagerImplTest#testNotifyNodeConnector

Fix test failure in TopologyManagerImplTest#testNotifyNodeConnector

Saw a sporadic test failure on jenkins:

java.lang.AssertionError: expected:<2> but was:<1>
        at org.junit.Assert.fail(Assert.java:88)
        at org.junit.Assert.failNotEquals(Assert.java:743)
        at org.junit.Assert.assertEquals(Assert.java:118)
        at org.junit.Assert.assertEquals(Assert.java:555)
        at org.junit.Assert.assertEquals(Assert.java:542)
        at
org.opendaylight.controller.topologymanager.internal.TopologyManagerImplTest.testNotifyNodeConnector(TopologyManagerImplTest.java:835)

The test flushes the pending queue and does a 1 sec sleep before
asserting but that might not be enough time so I added a 5 sec loop to
verify the expected edges map size.

Change-Id: Id7deaab93888819b71c286ca85864068f4d5dac6
Signed-off-by: Tom Pantelis <tpanteli@brocade.com>