Utils: Rename FileName to FilePath

More in line with QFileInfo terminonlogy which appears to be
best-of-breed within Qt.

Change-Id: I1d051ff1c8363ebd4ee56376451df45216c4c9ab
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/cpptools/modelmanagertesthelper.cpp

@@ -37,7 +37,7 @@ using namespace CppTools::Internal;
 using namespace CppTools::Tests;
 
 TestProject::TestProject(const QString &name, QObject *parent) :
-    ProjectExplorer::Project("x-binary/foo", Utils::FileName()),
+    ProjectExplorer::Project("x-binary/foo", Utils::FilePath()),
     m_name(name)
 {
     setParent(parent);