Remove grenade config workaround
Remove grenade config workaround

Starting with Idede322190d57491d4f7e18090aa8c29b5b87353 base and target
releases has the same tempest config file. This patch drops setting
fixed_network_name in target tempest.conf workaround.

Change-Id: I661ace60bf9b4817f73aaccda9c18e24adfc4e56

openstack/ironic,SauloAislan/ironic,openstack/ironic,pshchelo/ironic,pshchelo/ironic,NaohiroTamura/ironic,SauloAislan/ironic,NaohiroTamura/ironic