added shutdown executable

bin/CMakeLists.txt

 add_executable(hepnos-daemon hepnos-daemon.cpp)
 target_link_libraries(hepnos-daemon hepnos-service yaml-cpp margo bake-server sdskv-server)
 
+add_executable(hepnos-shutdown hepnos-shutdown.cpp)
+target_link_libraries(hepnos-shutdown hepnos yaml-cpp margo)
+
+install(TARGETS hepnos-shutdown DESTINATION bin)
 install(TARGETS hepnos-daemon DESTINATION bin)

bin/hepnos-shutdown.cpp

+#include <iostream>
+#include <hepnos.hpp>
+
+int main(int argc, char* argv[])
+{
+    if(argc != 2) {
+        std::cerr << "Usage: " << argv[0] << " <connection.yaml>" << std::endl;
+        exit(-1);
+    }
+
+    hepnos::DataStore datastore(argv[1]);
+    datastore.shutdown();
+
+    return 0;
+}