buttons: fix PushedTexture

this fixes textures for buttons in MacroFrame, SpellBook (tab buttons) and professions

api/ui-widgets.lua

@@ -417,6 +417,7 @@ function pfUI.api.SkinButton(button, cr, cg, cb, icon, disableHighlight)
 
   if icon then
     HandleIcon(b, icon)
+    b:SetPushedTexture(nil)
   end
 
   b:SetFont(pfUI.font_default, pfUI_config.global.font_size, "OUTLINE")

skins/blizzard/professions.lua

@@ -179,6 +179,7 @@ pfUI:RegisterSkin("Profession", "vanilla:tbc", function ()
         icon:ClearAllPoints()
         icon:SetPoint("TOPLEFT", 5, -5)
         SkinButton(icon, nil, nil, nil, nil, true)
+        icon:SetPushedTexture(nil)
 
         seltitle:SetJustifyV("TOP")
         seltitle:SetTextColor(.8,.8,.8,1)