Fixed the test failure of MinaConcurrencyTest

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org.apache.camel.component.mina.MinaConcurrencyTest.testConcurrentInOnly =================
junit.framework.AssertionFailedError: Clients should not wait for processing
at junit.framework.Assert.fail(Assert.java:47)
at junit.framework.Assert.assertTrue(Assert.java:20)
at org.apache.camel.component.mina.MinaConcurrencyTest.testConcurrentInOnly(MinaConcurrencyTest.java:59)