Fix an unit test: the test was failing because of upper-lower
case mismatch of a hex-string.
The issue was introduced after the toString() implementation
of MACAddress was simplified in commit 1906eb3ef0e337d2914924e0d06dba61d94a8fe9
diff --git a/src/test/java/net/floodlightcontroller/util/MACAddressTest.java b/src/test/java/net/floodlightcontroller/util/MACAddressTest.java
index 5669614..f19eedb 100644
--- a/src/test/java/net/floodlightcontroller/util/MACAddressTest.java
+++ b/src/test/java/net/floodlightcontroller/util/MACAddressTest.java
@@ -18,7 +18,7 @@
         address = MACAddress.valueOf("FF:FE:FD:10:20:30");
         assertEquals(address,
                 MACAddress.valueOf(new byte[]{(byte) 0xFF, (byte) 0xFE, (byte) 0xFD, 0x10, 0x20, 0x30}));
-        assertEquals("FF:FE:FD:10:20:30", address.toString());
+        assertEquals("ff:fe:fd:10:20:30", address.toString());
         
         address = MACAddress.valueOf("00:11:22:aa:bb:cc");
         assertEquals(address,