Bug2442: Windows crash when import exhausts disk space...

... Fixed by changing a move constructor to a copy constructor for the
exception object.  Not sure why that should be needed, according to the C++
standard, but so it is with the MSVC compiler.

src/FileException.h

@@ -25,8 +25,8 @@ public:
    , cause{ cause_ }, fileName{ fileName_ }, renameTarget{ renameTarget_ }
    {}
 
-   FileException(FileException&& that)
-      : MessageBoxException(std::move(that))
+   FileException( const FileException &that )
+      : MessageBoxException( that )
       , cause{ that.cause }
       , fileName{ that.fileName }
       , renameTarget{ that.renameTarget }