ocfs2: correctly set i_blocks after inline dir gets expanded

We were setting i_blocks based on allocation before the extent insert, which
is wrong as the value is a calculation based on ip_clusters which gets
updated as a result of the insert. This patch moves the line in question
to just after the call to ocfs2_insert_extent().

Without this fix, inline directories were temporarily having an i_blocks
value of zero immediately after expansion to extents.

Reported-and-tested-by: Tristan Ye <tristan.ye@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>