Since 964ab7158c, we explicitly set the bridge MTU if it was specified.
Unfortunately, kernel <v4.17 have a check preventing us to manually set
the MTU to anything greater than 1500 if no links is attached to the
bridge, which is how we do things -- create the bridge, set its MTU and
later on, attach veths to it.
Relevant kernel commit: 804b854d37
As we still have to support CentOS/RHEL 7 (and their old v3.10 kernels)
for a few more months, we need to ignore EINVAL if the MTU is > 1500
(but <= 65535).
Signed-off-by: Albin Kerouanton <albinker@gmail.com>
(cherry picked from commit 89470a7114)
Signed-off-by: Albin Kerouanton <albinker@gmail.com>
7a659049b8