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/coreplugin/externaltool.h

@@ -145,7 +145,7 @@ private:
     bool resolve();
 
     const ExternalTool *m_tool; // is a copy of the tool that was passed in
-    Utils::FileName m_resolvedExecutable;
+    Utils::FilePath m_resolvedExecutable;
     QString m_resolvedArguments;
     QString m_resolvedInput;
     QString m_resolvedWorkingDirectory;