ebos: disable writing restart files

this means eWoms specific .ers files, Eclipse restart files are still
written for visualization purposes.

applications/ebos/eclproblem.hh

@@ -395,6 +395,12 @@ public:
         return this->simulator().episodeWillBeOver();
     }
 
+    /*!
+     * \brief Returns true if an eWoms restart file should be written to disk.
+     */
+    bool shouldWriteRestartFile() const
+    { return false; }
+
     /*!
      * \brief Write the requested quantities of the current solution into the output
      *        files.