ext4: remove unused code from ext4_remove_blocks()

ext4: remove unused code from ext4_remove_blocks()

The "head removal" branch in the condition is never used in any code
path in ext4 since the function only caller ext4_ext_rm_leaf() will make
sure that the extent is properly split before removing blocks. Note that
there is a bug in this branch anyway.

This commit removes the unused code completely and makes use of
ext4_error() instead of printk if dubious range is provided.

Signed-off-by: Lukas Czerner <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>