test: unpack_properties: remove unused boost include

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I30e8752b4d3a8951dd1352126b8664fa5b8f53aa
diff --git a/test/unpack_properties.cpp b/test/unpack_properties.cpp
index 4e0db9c..64038bb 100644
--- a/test/unpack_properties.cpp
+++ b/test/unpack_properties.cpp
@@ -1,4 +1,3 @@
-#include <boost/container/flat_map.hpp>
 #include <sdbusplus/unpack_properties.hpp>
 
 #include <gmock/gmock.h>