Make compilation faster by moving print of git hash.

lib/util/version.cc

@@ -0,0 +1,12 @@
+#include <iostream>
+#include <version.h>
+namespace Grid {
+  void printHash(){
+#ifdef GITHASH
+    std::cout << "Current Grid git commit hash=" << GITHASH << std::endl;
+#else
+    std::cout << "Current Grid git commit hash is undefined. Check makefile." << std::endl;
+#endif
+#undef GITHASH
+}
+}