sheep/http: don't call oalloc_free() when onode is inlined

The inlined-onode does not contain any extent, so we don't need to free any space.
And, if we call oalloc_free(), it will pass wrong arguments ( onode->o_extent[0].start
and onode->o_extent[0].count) to oalloc_free().

Signed-off-by: Robin Dong <sanbai@taobao.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
sheep/http: use INODE_SET_VID_RANGE to accelerate speed of oalloc_free()

Use INODE_SET_VID_RANGE to set vid is more effecient for IO operaion, and,
after set vid to zero, we only need to REMOVE_OBJ (not DISCARD_OBJ).

Signed-off-by: Robin Dong <sanbai@taobao.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>