QmlJS: Ensure project infos are removed when a project closes.

As a side effect, this removes parse errors of QML files that are no
longer in any project from the "Build Issues" list.

Change-Id: I7aef8850a207ac060648dc92e2dd759108b71731
Reviewed-on: http://codereview.qt.nokia.com/3668
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@nokia.com>

src/libs/qmljs/qmljsmodelmanagerinterface.h

@@ -131,6 +131,7 @@ public:
     virtual QList<ProjectInfo> projectInfos() const = 0;
     virtual ProjectInfo projectInfo(ProjectExplorer::Project *project) const = 0;
     virtual void updateProjectInfo(const ProjectInfo &pinfo) = 0;
+    Q_SLOT virtual void removeProjectInfo(ProjectExplorer::Project *project) = 0;
 
     virtual QStringList importPaths() const = 0;