[GFS2] Merge gfs2_alloc_meta and gfs2_alloc_data

Thanks to the preceeding patches, the only difference between
these two functions is their name. We can thus merge them
and call the new function gfs2_alloc_block to reflect the
fact that it can allocate either kind of block.

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

fs/gfs2/dir.c

@@ -803,7 +803,7 @@ got_dent:
 static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh, u16 depth)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
-	u64 bn = gfs2_alloc_meta(ip);
+	u64 bn = gfs2_alloc_block(ip);
 	struct buffer_head *bh = gfs2_meta_new(ip->i_gl, bn);
 	struct gfs2_leaf *leaf;
 	struct gfs2_dirent *dent;