[Ide] Work around bug in Xamarin.Forms multi project templates

The templating engine creates all the outputs correctly, but PrimaryOutputs
contains the files containing the "sourceName" from the template
("NewApp" in the Xamarin.Forms case), not the real names of the files
on disk (NewApp.csproj instead of $ProjectName.csproj).

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1016597

Author: Rodrigo Moya

main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.Templates/MicrosoftTemplateEngineProjectTemplatingProvider.cs

@@ -105,6 +105,12 @@ public async Task<ProcessedTemplateResult> ProcessTemplate (SolutionTemplate tem
 			//TODO: Once templates support "D396686C-DE0E-4DE6-906D-291CD29FC5DE" use that to load projects
 			foreach (var path in result.ResultInfo.PrimaryOutputs) {
 				var fullPath = Path.Combine (config.ProjectLocation, GetPath (path));
+				if (!File.Exists (fullPath)) {
+					// Work around a bug in the templating engine with multi project templates
+					// See https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1016597
+					fullPath = fullPath.Replace ("NewApp", config.ProjectName);
+				}
+
 				if (Services.ProjectService.IsSolutionItemFile (fullPath))
 					workspaceItems.Add (await MonoDevelop.Projects.Services.ProjectService.ReadSolutionItem (new Core.ProgressMonitor (), fullPath));
 			}