refs #5467 fix -Wmaybe-uninitialized warning when compiling with optimizations

since enums can be implicitly cast from ints, switch statement type safety
doesn't really work, but the compiler only catches it if it tries to do a
certain amount of CCP


git-svn-id: file:///svn/toku/tokudb@47892 c7de825b-a66e-492c-adef-691d508d4ae1

ft/checkpoint.cc

@@ -227,6 +227,8 @@ static bool checkpoint_caller_is_aggressive(checkpoint_caller_t caller_id) {
     case SHUTDOWN_CHECKPOINT:
         retval = true;
         break;
+    default:
+        abort();
     }
     return retval;
 }