Revert "Require aclocal 1.11.1 or above for autogen.sh"

The comparison is incorrect, and the check also breaks daily work on
autobuilders and older distros.

This reverts commit dbc4dda7.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>