Only disable legacy bridging if an existing network.device section with type bridge is found, ignore non-type sections since those do not declare a bridge but set attributes on top of an existing one. Signed-off-by: Jo-Philipp Wich <jo@mein.io> (cherry picked from commit f48f9f11e7f6e3d74e2fd4b6b2478e5673f2f459)