Fix random TestDataSourceComponent.testNonShared

java.lang.AssertionError: expected:<4> but was:<3>
	at org.junit.Assert.fail(Assert.java:89)
	at org.junit.Assert.failNotEquals(Assert.java:835)
	at org.junit.Assert.assertEquals(Assert.java:647)
	at org.junit.Assert.assertEquals(Assert.java:633)
	at org.nuxeo.runtime.datasource.TestDataSourceComponent.testNonShared(TestDataSourceComponent.java:92)