entity-manager: Search sysconfdir for configurations

Make it easier to iteratively develop configurations in-place with a
read-only /usr.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: Id0853b579a61394cb2b6ef0a3858ba01e5cb2893
diff --git a/src/FruDevice.cpp b/src/FruDevice.cpp
index c774b65..8159f84 100644
--- a/src/FruDevice.cpp
+++ b/src/FruDevice.cpp
@@ -41,6 +41,7 @@
 #include <iomanip>
 #include <iostream>
 #include <limits>
+#include <map>
 #include <regex>
 #include <set>
 #include <sstream>