INTSAMPLES-102 - Fix intermittently failing tests

Reference: https://jira.springsource.org/browse/INTSAMPLES-102

basic/ftp/src/test/java/org/springframework/integration/samples/ftp/FtpInboundChannelAdapterSample.java

@@ -54,6 +54,7 @@ public class FtpInboundChannelAdapterSample {
 		assertNotNull(message2);
 		assertNull("Was NOT expecting a third message.", message3);
 
+		ctx.close();
 	}
 
 }

basic/ftp/src/test/java/org/springframework/integration/samples/ftp/FtpOutboundGatewaySample.java

@@ -66,6 +66,7 @@ public class FtpOutboundGatewaySample {
 
 		assertTrue("Expected FTP remote directory to be empty",  new File(TestSuite.FTP_ROOT_DIR).delete());
 
+		ctx.close();
 	}
 
 }