This patch corrects the return value for the EXT3_IOC_GROUP_ADD in case
it fails due to the presence of multiple resizers at the filesystem.
The problem is a little bit more serious than a wrong return value in
this case, since the clause err=0 in the exit_journal path will lead to
a call to update_backups which in turns causes a NULL pointer
dereference.
Signed-off-by: Glauber de Oliveira Costa <[email protected]>