Hold checkpoint_safe lock when setting callback, clear callback at end of test.

git-svn-id: file:///svn/toku/tokudb@11320 c7de825b-a66e-492c-adef-691d508d4ae1

src/tests/checkpoint_1.c

@@ -327,7 +327,8 @@ test_main (int argc, const char *argv[]) {
     }
 
     db_env_set_checkpoint_callback(checkpoint_callback, (void*) test_dictionary);
-    runtests(0,4,1);
+    runtests(0,4096,1);
+    db_env_set_checkpoint_callback(NULL, NULL);
 
     return 0;
 }

src/ydb.c

@@ -3818,6 +3818,8 @@ void setup_dlmalloc (void) {
 // For test purposes only.
 // With this interface, all checkpoint users get the same callback and the same extra.
 void db_env_set_checkpoint_callback (void (*callback_f)(void*), void* extra) {
+    toku_checkpoint_safe_client_lock();
     checkpoint_callback_f = callback_f;
     checkpoint_callback_extra = extra;
+    toku_checkpoint_safe_client_unlock();
 }