storagecommands: add functional header

The functional header provides std::hash

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I48451b1278a3d53e0d0622e72590a8ac7d9bd53d
diff --git a/src/storagecommands.cpp b/src/storagecommands.cpp
index c89ad82..62cd12e 100644
--- a/src/storagecommands.cpp
+++ b/src/storagecommands.cpp
@@ -19,6 +19,7 @@
 #include <boost/process.hpp>
 #include <commandutils.hpp>
 #include <filesystem>
+#include <functional>
 #include <iostream>
 #include <ipmi_to_redfish_hooks.hpp>
 #include <ipmid/api.hpp>