[GFS2] soft lockup in rgblk_search

This patch seems to fix the problem described in bugzilla bug 246114.
It was written by Steve Whitehouse with some tweaking by me.

The code was looping in the relatively new section of code designed to
search for and reuse unlinked inodes.  In cases where it was finding an
appropriate inode to reuse, it was looping around and finding the same
block over and over because a "<=" check should have been a "<" when
comparing the goal block to the last unlinked block found.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>