chore(version-info): make online build compatible with Windows

Since we cannot write to dev/null on Windows, don't write to a file at all, but simply use stdout and extract the output from --write-out from the process response. Credit to @petebacondarwin for the idea.

The commit also avoids a premature error when no cdnVersion could be found online, and improves the log wrt the origin of the versions.

PR (#14780)

lib/versions/version-info.js

@@ -9,6 +9,7 @@ var _ = require('lodash');
 var process = require('process');
 // We are only interested in whether this environment variable exists, hence the !!
 var NO_REMOTE_REQUESTS = !!process.env['NG1_BUILD_NO_REMOTE_VERSION_REQUESTS'];
+var versionSource = NO_REMOTE_REQUESTS ? 'local' : 'remote';
 
 var currentPackage, previousVersions, cdnVersion, gitRepoInfo;
 
@@ -149,10 +150,11 @@ var getCdnVersion = function() {
           // Note: need to use shell.exec and curl here
           // as version-infos returns its result synchronously...
           var cdnResult = shell.exec('curl http://ajax.googleapis.com/ajax/libs/angularjs/' + version + '/angular.min.js ' +
-                    '--head --write-out "%{http_code}" -o /dev/null -silent',
+                    '--head --write-out "%{http_code}" -silent',
                                       {silent: true});
           if (cdnResult.code === 0) {
-            var statusCode = cdnResult.output.trim();
+            // --write-out appends its content to the general request response, so extract it
+            var statusCode = cdnResult.output.split('\n').pop().trim();
             if (statusCode === '200') {
               cdnVersion = version;
             }
@@ -221,5 +223,6 @@ if (NO_REMOTE_REQUESTS) {
   console.log(' - be aware that the generated docs may not have valid or the most recent version information.');
   console.log('==============================================================================================');
 }
-console.log('CDN version:', cdnVersion.raw);
-console.log('Current version:', exports.currentVersion.raw);
+
+console.log('CDN version (' + versionSource + '):', cdnVersion ? cdnVersion.raw : 'No version found.');
+console.log('Current version (' + versionSource + '):', exports.currentVersion.raw);