ProjectExplorer: Make Project::id value based

Change-Id: Ie210d2a068158c6caaac66aae58cbd886f61c18d
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/qbsprojectmanager/qbsproject.cpp

@@ -102,6 +102,7 @@ QbsProject::QbsProject(QbsManager *manager, const QString &fileName) :
 {
     m_parsingDelay.setInterval(1000); // delay parsing by 1s.
 
+    setId(Constants::PROJECT_ID);
     setProjectContext(Context(Constants::PROJECT_ID));
     setProjectLanguages(Context(ProjectExplorer::Constants::LANG_CXX));
 
@@ -132,11 +133,6 @@ QString QbsProject::displayName() const
     return m_projectName;
 }
 
-Id QbsProject::id() const
-{
-    return Constants::PROJECT_ID;
-}
-
 IDocument *QbsProject::document() const
 {
     foreach (IDocument *doc, m_qbsDocuments) {