Update Travis CI Scripts (#2799)

Set `rc` tag to the publishConfig section for the release branch.

Author: Vasil Chimev

.travis.yml

@@ -24,7 +24,7 @@ after_success:
 - mkdir s3-publish
 - cp nativescript*.tgz s3-publish/nativescript.tgz
 before_deploy:
-- node .travis/add-publishConfig.js next
+- node .travis/add-publishConfig.js
 deploy:
   - provider: s3
     bucket: nativescript-ci
@@ -43,3 +43,10 @@ deploy:
       branch: master
     api_key:
       secure: KzzsvF3eA3j4gRQa8tO//+XWNSR3XiX8Sa18o3PyKyG9/cBZ6PQ3Te74cNS1C3ZiLUOgs5dWA6/TmRVPci4XjvFaWo/B6e2fuVSl5H94Od99bkeBHJsbLSEkLN4ClV/YbGuyKgA5Q2yIFt6p2EJjL90RjbbIk7I4YuyG2Mo3j0Q=
+  - provider: npm
+    skip_cleanup: true
+    email: nativescript@telerik.com
+    on:
+      branch: release
+    api_key:
+      secure: KzzsvF3eA3j4gRQa8tO//+XWNSR3XiX8Sa18o3PyKyG9/cBZ6PQ3Te74cNS1C3ZiLUOgs5dWA6/TmRVPci4XjvFaWo/B6e2fuVSl5H94Od99bkeBHJsbLSEkLN4ClV/YbGuyKgA5Q2yIFt6p2EJjL90RjbbIk7I4YuyG2Mo3j0Q=

.travis/add-publishConfig.js

@@ -2,24 +2,23 @@
 
 var fsModule = require('fs');
 
-//Adds a publishConfig section to the package.json file
+// Adds a publishConfig section to the package.json file
 // and sets a tag to it
 
 var path = './package.json';
 var fileOptions = {encoding: "utf-8"};
 var content = fsModule.readFileSync(path, fileOptions);
 
-var tag = process.argv[2];
-if (!tag) {
-    console.log('Please pass the tag name as an argument!');
-    process.exit(1);
-}
-
 var packageDef = JSON.parse(content);
 if (!packageDef.publishConfig) {
     packageDef.publishConfig = {};
 }
-packageDef.publishConfig.tag = tag;
+
+if ($TRAVIS_BRANCH === 'release') {
+    packageDef.publishConfig.tag = 'rc';
+} else {
+    packageDef.publishConfig.tag = 'next';
+}
 
 var newContent = JSON.stringify(packageDef, null, '  ');
-fsModule.writeFileSync(path, newContent, fileOptions);
+fsModule.writeFileSync(path, newContent, fileOptions);