Fix typo and a bug causing vnode references to become too low.

servers/vfs/stadir.c

@@ -37,6 +37,7 @@ PUBLIC int do_fchdir()
 
   /* Is the file descriptor valid? */
   if ((rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
+  dup_vnode(rfilp->filp_vno);	/* Change into expects a reference. */
   return change_into(&fp->fp_wd, rfilp->filp_vno);
 }
 

servers/vfs/vnode.c

@@ -136,7 +136,7 @@ PUBLIC void put_vnode(struct vnode *vp)
   vp->v_sdev = NO_DEV;
   vp->v_mapfs_e = 0;
   vp->v_mapinode_nr = 0;
-  vp->v_fs_count = 0;
+  vp->v_mapfs_count = 0;
 }