mke2fs: correct help text for option -G of mke2fs

The option '-G' is used to pass number of groups in a flex_bg, the
previous help text - 'meta-group-size' - could confuse users with
meta_bg.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed