FileUtils: Replace FileNameList with an alias

The functionality in that class is covered by initializers and
Utils::unique, so there is no need to keep a custom class.

This way FileNameList plays way nicer with utils/algorithm.h.

Change-Id: I8eeae6aca0558ecd998920c4fdfc5ea56bf75501
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/cpptools/cpptoolsreuse.h

@@ -37,6 +37,8 @@
 
 #include <cplusplus/CppDocument.h>
 
+#include <utils/fileutils.h>
+
 QT_BEGIN_NAMESPACE
 class QChar;
 class QFileInfo;
@@ -44,10 +46,6 @@ class QStringRef;
 class QTextCursor;
 QT_END_NAMESPACE
 
-namespace Utils {
-class FileNameList;
-} // namespace Utils
-
 namespace CPlusPlus {
 class Macro;
 class Symbol;