Make state change in wxProgressDialog::Resume() more explicit

Reset the state to "Continue" instead of assigning it the dialogs own
m_state which was also set to "Continue" from the base class Resume()
called just before, but this wasn't necessarily obvious from just
reading the code.

No real changes.

src/msw/progdlg.cpp

@@ -543,7 +543,7 @@ void wxProgressDialog::Resume()
 
         {
             wxCriticalSectionLocker locker(m_sharedData->m_cs);
-            m_sharedData->m_state = m_state;
+            m_sharedData->m_state = Continue;
 
             // "Skip" was disabled when "Cancel" had been clicked, so re-enable
             // it now.