add missing import. fixes 7bbc22a

Author: kofemann

core/src/main/java/org/dcache/nfs/v4/FileTracker.java

@@ -32,6 +32,7 @@
 import org.dcache.nfs.status.BadStateidException;
 import org.dcache.nfs.status.InvalException;
 import org.dcache.nfs.status.ShareDeniedException;
+import org.dcache.nfs.v4.xdr.nfs4_prot;
 import org.dcache.nfs.v4.xdr.stateid4;
 import org.dcache.nfs.vfs.Inode;
 import org.dcache.nfs.util.Opaque;