(GH-1724) search - exit 1 on no results

Instead of exiting with 0 if no results are found, exit with something
different to indicate that nothing was found. 0 would indicate a
success that there was results, where 1 would indicate something isn't
quite right if there was an expectation of finding something.

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

@@ -16,6 +16,7 @@
 
 namespace chocolatey.infrastructure.app.commands
 {
+    using System;
     using System.Collections.Generic;
     using System.Linq;
     using attributes;
@@ -201,7 +202,13 @@ public virtual void run(ChocolateyConfiguration configuration)
         {
             _packageService.ensure_source_app_installed(configuration);
             // note: you must leave the .ToList() here or else the method won't be evaluated!
-            _packageService.list_run(configuration).ToList();
+            var packageResults = _packageService.list_run(configuration).ToList();
+
+            // if there are no results, exit with a 1.
+            if (packageResults.Count == 0)
+            {
+                Environment.ExitCode = 1;
+            }
         }
 
         public virtual IEnumerable<PackageResult> list(ChocolateyConfiguration configuration)