Remove omp variable from non openmp kernels (#211)

* Remove openmp reference non openmp kernel

Author: mcbarton

share/jupyter/kernels/xcpp17/kernel.json.in

@@ -10,7 +10,7 @@
       "{connection_file}",
       "-resource-dir", "@XEUS_CPP_RESOURCE_DIR@",
       "-I", "@XEUS_CPP_INCLUDE_DIR@",
-      "-std=c++17"@XEUS_CPP_OMP@
+      "-std=c++17"
   ],
   "language": "cpp",
   "metadata": {"debugger": false

share/jupyter/kernels/xcpp20/kernel.json.in

@@ -10,7 +10,7 @@
       "{connection_file}",
       "-resource-dir", "@XEUS_CPP_RESOURCE_DIR@",
       "-I", "@XEUS_CPP_INCLUDE_DIR@",
-      "-std=c++20"@XEUS_CPP_OMP@
+      "-std=c++20"
   ],
   "language": "cpp",
   "metadata": {"debugger": false