resize2fs: clear uninit BG if allocating from new group

resize2fs: clear uninit BG if allocating from new group

If resize2fs_get_alloc_block() allocates from a BLOCK_UNINIT group, we
need to make sure that the UNINIT flag is cleared on both file system
structures which are maintained by resize2fs.  This causes the
modified bitmaps to not get written out, which leads to post-resize2fs
e2fsck errors; used blocks in UNINIT groups, not marked in the block
bitmap.  This was seen on r_ext4_small_bg.

This patch uses clear_block_uninit() to clear the flag,
and my problem goes away.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>