Change fs functions to add fs_ prefix

This avoid conflict with gnulib

Signed-off-by: Vladimir Serbinenko <phcoder@google.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/fs/jfs.c

@@ -930,12 +930,12 @@ grub_jfs_label (grub_device_t device, char **label)
 static struct grub_fs grub_jfs_fs =
   {
     .name = "jfs",
-    .dir = grub_jfs_dir,
-    .open = grub_jfs_open,
-    .read = grub_jfs_read,
-    .close = grub_jfs_close,
-    .label = grub_jfs_label,
-    .uuid = grub_jfs_uuid,
+    .fs_dir = grub_jfs_dir,
+    .fs_open = grub_jfs_open,
+    .fs_read = grub_jfs_read,
+    .fs_close = grub_jfs_close,
+    .fs_label = grub_jfs_label,
+    .fs_uuid = grub_jfs_uuid,
 #ifdef GRUB_UTIL
     .reserved_first_sector = 1,
     .blocklist_install = 1,