move namespaceMap into web/util

src/platforms/web/runtime/class-util.js

@@ -1,5 +1,4 @@
-import { isIE9 } from 'web/util/index'
-import { namespaceMap } from './node-ops'
+import { isIE9, namespaceMap } from 'web/util/index'
 
 const svgNS = namespaceMap.svg
 

src/platforms/web/runtime/node-ops.js

@@ -1,7 +1,4 @@
-export const namespaceMap = {
-  svg: 'http://www.w3.org/2000/svg',
-  math: 'http://www.w3.org/1998/Math/MathML'
-}
+import { namespaceMap } from 'web/util/index'
 
 export function createElement (tagName) {
   return document.createElement(tagName)

src/platforms/web/util/element.js

@@ -1,6 +1,11 @@
 import { inBrowser } from 'core/util/env'
 import { makeMap } from 'shared/util'
 
+export const namespaceMap = {
+  svg: 'http://www.w3.org/2000/svg',
+  math: 'http://www.w3.org/1998/Math/MathML'
+}
+
 export const isReservedTag = makeMap(
   'html,base,head,link,meta,style,title,' +
   'address,article,footer,header,h1,h2,h3,h4,h5,h6,hgroup,nav,section,' +