Remove redundant arguments from fstream constructors

Don't pass the default value of the openmode parameter explicitly.

Tests/AliasTarget/commandgenerator.cpp

@@ -5,8 +5,7 @@
 
 int main(int argc, char** argv)
 {
-  std::fstream fout;
-  fout.open("commandoutput.h", std::ios::out);
+  std::ofstream fout("commandoutput.h");
   if (!fout)
     return 1;
   fout << "#define COMMANDOUTPUT_DEFINE\n";