Add add-ons directory to sdk so ant build does not try to create directory.
Add add-ons directory to sdk so ant build does not try to create directory.

yongjhih/android_tools,yongjhih/android_tools,yongjhih/android_tools,yongjhih/android_tools,yongjhih/android_tools,yongjhih/android_tools,yongjhih/android_tools,yongjhih/android_tools