/give @p iron_sword 1 0 {ench:[{id:16,lvl:1}],AttributeModifiers:[{Operation:0,UUIDLeast:1,UUIDMost:1,Amount:6.0,AttributeName:generic.attackDamage,Name:attackDamage}]}Attribute attackDamage over writes all information of enchantments dealing with attack power. (IE: Sharpness, Smite, Bane of A.)
Keep in mind when dealing with this solution it may be possible to cause another bug where the swords previous damage may stack with both of these.
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.