You need to edit Spell.dbc. Using Stoneharry's Spell Editor is a good method of doing this.
You want to look up the spellID from a database. Using Razorice with ID 53343 as an example. Open it up in spell editor and change
Requires Spell Focus to none. It's under "Base" tab.
Here is a screenshot of the looks. Top right - not sure if you'll need to distribute it to clients, or if having a server is enough. Might be just fine to be serverside but clientside it'll be saying "Requires: Runeforge" still.