[OMPT] Fix tool initialization returning 0

[protze.joachim]

Summary

If tool initialization returns 0, OMPT should not be active. The current implementation provided some callback invocations in this case.

[hbae]

LGTM.
Don't forget to do clang-formatting.

[omalyshe]

LGTM.

openmp/trunk/runtime/src/ompt-general.cpp

void ompt_post_init() {
 
   //--------------------------------------------------
   // Initialize the tool if so indicated.
   //--------------------------------------------------
   if (ompt_start_tool_result) {
     ompt_enabled.enabled = !!ompt_start_tool_result->initialize(
         ompt_fn_lookup, &(ompt_start_tool_result->tool_data));
 
+    if (!ompt_enabled.enabled) {
+      // tool not enabled, zero out the bitmap, and done
+      memset(&ompt_enabled, 0, sizeof(ompt_enabled));
+      return;
+    }
+
     ompt_thread_t *root_thread = ompt_get_thread();
 
     ompt_set_thread_state(root_thread, omp_state_overhead);
 
     if (ompt_enabled.ompt_callback_thread_begin) {
       ompt_callbacks.ompt_callback(ompt_callback_thread_begin)(
           ompt_thread_initial, __ompt_get_thread_data_internal());
     }