oss-fuzz: fixed wrong lib path
the logical-fields.h file was moved. Path has been updated
accordingly. This broke oss-fuzz buils.
CC: Numan Siddique
Fixes: ("ovn: Add a new OVN field icmp4.frag_mtu")
#include "ovn/actions.h"
#include "ovn/expr.h"
#include "ovn/lex.h"
-#include "ovn/lib/logical-fields.h"
+#include "ovn/logical-fields.h"
#include "ovn/lib/ovn-l7.h"
#include "ovn/lib/extend-table.h"
#include "openvswitch/shash.h"
