cppcheck: fix some duplicates warnings
Plugins/GMVReader/Reader/gmvread.c:3755:39: style: The if condition is the same as the previous if condition [duplicateCondition]
Remoting/ClientServerStream/vtkClientServerStream.cxx:3109:33: style: Same expression on both sides of '-'. [duplicateExpression]
Edited by Mathieu Westphal (Kitware)