[xbuild] Update regex to not require EndProject in a sln file.

In a solution file, a Project might not have a corresponding
EndProject. This seems to be supported by VS, so updating xbuild
to support that too. Updated the regex.

mcs/tools/xbuild/SolutionParser.cs

@@ -93,7 +93,7 @@ namespace Mono.XBuild.CommandLine {
 		static string guidExpression = "{[A-Fa-f0-9]{8}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{12}}";
 
 		static Regex slnVersionRegex = new Regex (@"Microsoft Visual Studio Solution File, Format Version (\d?\d.\d\d)");
-		static Regex projectRegex = new Regex ("Project\\(\"(" + guidExpression + ")\"\\) = \"(.*?)\", \"(.*?)\", \"(" + guidExpression + ")\"(\\s*?)((\\s*?)ProjectSection\\((.*?)\\) = (.*?)EndProjectSection(\\s*?))*(\\s*?)EndProject?", RegexOptions.Singleline);
+		static Regex projectRegex = new Regex ("Project\\(\"(" + guidExpression + ")\"\\) = \"(.*?)\", \"(.*?)\", \"(" + guidExpression + ")\"(\\s*?)((\\s*?)ProjectSection\\((.*?)\\) = (.*?)EndProjectSection(\\s*?))*(\\s*?)(EndProject)?", RegexOptions.Singleline);
 		static Regex projectDependenciesRegex = new Regex ("ProjectSection\\((.*?)\\) = \\w*(.*?)EndProjectSection", RegexOptions.Singleline);
 		static Regex projectDependencyRegex = new Regex ("\\s*(" + guidExpression + ") = (" + guidExpression + ")");
 		static Regex projectSectionPropertiesRegex = new Regex ("\\s*(?<name>.*) = \"(?<value>.*)\"");