6838211: jdk docs creation broken for tracing docs

Fix javadoc makefile macro

Reviewed-by: ohair, jjg
diff --git a/jdk/make/docs/Makefile b/jdk/make/docs/Makefile
index 301acde..aa58f76 100644
--- a/jdk/make/docs/Makefile
+++ b/jdk/make/docs/Makefile
@@ -620,7 +620,7 @@
 	@# ######## api-tracing ############################
 	$(RM) -r $(TRACING_DOCDIR)
 	$(MKDIR) -p $(TRACING_DOCDIR)
-	$(JAVADOC) $(TRACING_JAVADOCFLAGS)                     \
+	$(JAVADOC_CMD) $(TRACING_JAVADOCFLAGS)                     \
 		   $(TRACING_PKGS)
 
 .PHONY: httpserverdocs