[GFS2] fs/gfs2/dir.c:gfs2_dir_write_data(): don't use an uninitialized variable

In the "if (extlen)" case, "new" might be used uninitialized.

Looking at the code, it should be initialized to 0.

Spotted by the Coverity checker.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>