Raise an internal error instead of an unknown error

Author: pblottiere

src/server/services/wms/qgswmsgetlegendgraphics.cpp

@@ -96,8 +96,7 @@ namespace QgsWms
     }
     else
     {
-      throw QgsServiceException( QStringLiteral( "UnknownError" ),
-                                 QStringLiteral( "Failed to compute GetLegendGraphics image" ) );
+      throw QgsException( QStringLiteral( "Failed to compute GetLegendGraphics image" ) );
     }
   }
 } // namespace QgsWms

src/server/services/wms/qgswmsgetmap.cpp

@@ -57,8 +57,7 @@ namespace QgsWms
     }
     else
     {
-      throw QgsServiceException( QStringLiteral( "UnknownError" ),
-                                 QStringLiteral( "Failed to compute GetMap image" ) );
+      throw QgsException( QStringLiteral( "Failed to compute GetMap image" ) );
     }
   }
 } // namespace QgsWms