Presentation compiler: let ShutdownReq propagate from the background compiler, and don't mark a unit as crashed in that case.

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@25817 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

src/compiler/scala/tools/nsc/interactive/Global.scala

@@ -469,7 +469,8 @@ class Global(settings: Settings, reporter: Reporter, projectName: String = "")
           r set unit.body
         serviceParsedEntered()
       } catch {
-        case ex: FreshRunReq => throw ex // propagate a new run request
+        case ex: FreshRunReq => throw ex           // propagate a new run request
+        case ShutdownReq     => throw ShutdownReq  // propagate a shutdown request
         
         case ex =>
           println("[%s]: exception during background compile: ".format(unit.source) + ex)