Fill default VpcConfig to prevent errors (#183)

Author: DeviaVir

lib/main.js

@@ -122,7 +122,10 @@ Lambda.prototype._params = function (program, buffer) {
     MemorySize: program.memorySize,
     Timeout: program.timeout,
     Publish: program.publish,
-    VpcConfig: {},
+    VpcConfig: {
+      SubnetIds: [],
+      SecurityGroupIds: []
+    },
     Environment: {
       Variables: {}
     }

test/main.js

@@ -71,7 +71,8 @@ describe('node-lambda', function () {
 
     it('does not append VpcConfig when params are not set', function() {
       var params = lambda._params(program);
-      assert.equal(Object.keys(params.VpcConfig).length, 0);
+      assert.equal(Object.keys(params.VpcConfig.SubnetIds).length, 0);
+      assert.equal(Object.keys(params.VpcConfig.SecurityGroupIds).length, 0);
     });
 
     describe('configFile', function () {