qmljs: add explicit -relocatable flag to qmlplugindumper and use it

This will allow changing the default to nonrelocatable.

Change-Id: I80746a3e70f94040a407cc25cec9ad6fac8b6fec
Reviewed-by: Kai Koehne <kai.koehne@digia.com>

src/libs/qmljs/qmljsmodelmanagerinterface.h

@@ -57,12 +57,12 @@ public:
     {
     public:
         ProjectInfo()
-            : tryQmlDump(false)
+            : tryQmlDump(false), qmlDumpHasRelocatableFlag(true)
         { }
 
         ProjectInfo(QPointer<ProjectExplorer::Project> project)
             : project(project)
-            , tryQmlDump(false)
+            , tryQmlDump(false), qmlDumpHasRelocatableFlag(true)
         { }
 
         operator bool() const
@@ -83,6 +83,7 @@ public:
 
         // whether trying to run qmldump makes sense
         bool tryQmlDump;
+        bool qmlDumpHasRelocatableFlag;
         QString qmlDumpPath;
         ::Utils::Environment qmlDumpEnvironment;