update example to be able to run through initialization

examples/solidfluid/solidfluid.xml

 <?xml version="1.0"?>
-<adios-config>
+<adios-config host-language="C">
 
   <!--  Changes to ADIOS-1 XML
         Accommodate for the following extensions and flexiblity:

examples/solidfluid/solidfluid_write.cpp

@@ -6,7 +6,6 @@
  */
 
 #include <stdexcept>
-#include <mpi.h>
 #include <iostream>
 #include <fstream>
 #include <string>