Android: Fix compilation with warnings-are-errors

Variable was added in e2e874415e
but is not used anywhere.

Change-Id: Iff1e7c20317bb489978eb77d24b8da12493d7e45
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

src/plugins/platforms/android/androidjniclipboard.cpp

@@ -47,7 +47,6 @@ namespace QtAndroidClipboard
 {
     QAndroidPlatformClipboard *m_manager = nullptr;
 
-    static char const *const QtNativeClassName = "org/qtproject/qt5/android/QtNative";
     static JNINativeMethod methods[] = {
         {"onClipboardDataChanged", "()V", (void *)onClipboardDataChanged}
     };