[bugfix] Make parallel file merge work again for any --output-dir.

This fixes fallout from the merge of PR #1512. Since then the
ParallelFileMerger was always given the current directory even if
another output directory was requested. This resulted in
CASENAME.<procid>.<ext> files in that directory never being merged and removed.
Now the ParallelFileMerger gets the output directory path again.

opm/autodiff/FlowMainEbos.hpp

@@ -425,9 +425,8 @@ namespace Opm
             }
 
             namespace fs = boost::filesystem;
-            fs::path output_path(".");
             const std::string& output_dir = eclState().getIOConfig().getOutputDir();
-
+            fs::path output_path(output_dir);
             fs::path deck_filename(EWOMS_GET_PARAM(TypeTag, std::string, EclDeckFileName));
             std::for_each(fs::directory_iterator(output_path),
                           fs::directory_iterator(),