(chocolatey#62) Use DefaultPushSource if set

If the DefaultPushSource config value is not empty, use it as the
default source which to push packages. Using --source will override
it. It overrides the built-in default of using the
"ChocolateyCommunityFeedPushSource".

If --api-key is not passed and a api key has not been saved for the
DefaultPushSource, it will fail with the standard message about an api
key being required.

src/chocolatey/infrastructure.app/commands/ChocolateyPushCommand.cs

@@ -60,6 +60,11 @@ public virtual void handle_additional_argument_parsing(IList<string> unparsedArg
         {
             configuration.Input = string.Join(" ", unparsedArguments); // path to .nupkg - assume relative
 
+            if (string.IsNullOrWhiteSpace(configuration.Sources) && !string.IsNullOrWhiteSpace(configuration.PushCommand.DefaultSource))
+            {
+                configuration.Sources = configuration.PushCommand.DefaultSource;
+            }
+
             if (string.IsNullOrWhiteSpace(configuration.Sources))
             {
                 configuration.Sources = ApplicationParameters.ChocolateyCommunityFeedPushSource;