Unix: avoid false unmount success reports on retries

Skip success reporting after a failed first-pass unmount is queued for
retry. Cover successful, failed, and unconfirmed retries.

src/Main/UserInterface.cpp

@@ -302,7 +302,10 @@ namespace VeraCrypt
 					catch (...)
 					{
 						if (twoPassMode && firstPass)
+						{
 							volumesLeft.push_back (volume);
+							continue;
+						}
 						else
 							throw;
 					}