design-2.3.rst: fix whitespace
design-2.3.rst: fix whitespace

Signed-off-by: Adeodato Simo <16293852a0900193fe70fa7d24f714f37ba99a56@google.com>
Reviewed-by: Michael Hanselmann <68b67885ff74281219b4a4be33cc20fd45078d7c@google.com>

ganeti/ganeti,mbakke/ganeti,andir/ganeti,ganeti/ganeti,bitemyapp/ganeti,apyrgio/ganeti,yiannist/ganeti,apyrgio/snf-ganeti,ganeti-github-testing/ganeti-test-1,apyrgio/ganeti,mbakke/ganeti,onponomarev/ganeti,ganeti-github-testing/ganeti-test-1,onponomarev/ganeti,yiannist/ganeti,dimara/ganeti,andir/ganeti,ganeti/ganeti,grnet/snf-ganeti,leshchevds/ganeti,mbakke/ganeti,dimara/ganeti,bitemyapp/ganeti,grnet/snf-ganeti,leshchevds/ganeti,yiannist/ganeti,andir/ganeti,leshchevds/ganeti,apyrgio/snf-ganeti