(GH-1285) Default push to new or old w/warning

When pushing larger packages, the original push url was subject to a
timeout of 100 seconds, a limitation of using Cloudflare. The error:
`Error publishing package. NuGet server returned 524: Origin Time-out"
when pushing through the Cloudflare infrastructure. Instead, convert to
a new default push url that is not subject to a timeout by Cloudflare.

To ensure this is not a breaking change, determine whether the old
apikey was set and use it with a warning to change it over to use the
new url.

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

@@ -103,7 +103,7 @@ choco apikey
 
 ");
 
-            "chocolatey".Log().Info(ChocolateyLoggers.Important, "Connecting to Chocolatey.org");
+            "chocolatey".Log().Info(ChocolateyLoggers.Important, "Connecting to Chocolatey.org (Community Package Repository)");
             "chocolatey".Log().Info(() => @"
 In order to save your API key for {0}, 
  log in (or register, confirm and then log in) to

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

@@ -74,6 +74,28 @@ public virtual void handle_additional_argument_parsing(IList<string> unparsedArg
             if (string.IsNullOrWhiteSpace(configuration.Sources))
             {
                 configuration.Sources = ApplicationParameters.ChocolateyCommunityFeedPushSource;
+                var newSourceKey = _configSettingsService.get_api_key(configuration, null);
+
+                if (string.IsNullOrWhiteSpace(newSourceKey))
+                {
+                    configuration.Sources = ApplicationParameters.ChocolateyCommunityFeedPushSourceOld;
+                    var oldSourceKey = _configSettingsService.get_api_key(configuration, null);
+
+                    if (string.IsNullOrWhiteSpace(oldSourceKey))
+                    {
+                        configuration.Sources = ApplicationParameters.ChocolateyCommunityFeedPushSource;
+                    }
+                    else
+                    {
+                        this.Log().Warn(ChocolateyLoggers.Important, @"ACTION: Please update your apikey to use 
+  '{0}' 
+ instead of 
+  '{1}'. 
+ The latter source url is now considered deprecated and will not be 
+ checked as the default source in Chocolatey v1.0. For details, run 
+ `choco apikey -?`".format_with(ApplicationParameters.ChocolateyCommunityFeedPushSource, ApplicationParameters.ChocolateyCommunityFeedPushSourceOld));
+                    }
+                }
             }
 
             if (!string.IsNullOrWhiteSpace(configuration.Sources))