Oops should be version not build

Former-commit-id: c4aaa47617fc953e0ee0b44a81a83cc88be5ce4e
Former-commit-id: ecad1a94605ff23414586f1d7adde67b3b5ef4e1
Former-commit-id: f0bc37a41980f9876e85e299f751f628a3898b83

build/aspnet5-version.js

@@ -2,7 +2,7 @@
 var util = require('util');
 
 var file = '../src/imageprocessor/project.json';
-var buildNumber = process.env.APPVEYOR_BUILD_NUMBER;
+var buildNumber = process.env.APPVEYOR_BUILD_VERSION;
 
 jsonfile.readFile(file, function (err, project) {
     project.version = buildNumber;