COMP: Hash.H was not included with HashTable/HashSet

- was only included indirectly via FixedList.H

src/OpenFOAM/containers/HashTables/HashTable/HashTable.H

@@ -57,6 +57,7 @@ SourceFiles
 #include "uLabel.H"
 #include "word.H"
 #include "Xfer.H"
+#include "Hash.H"
 #include "className.H"
 #include "nullObject.H"