我使用txt文件启用了proguard但它生成了一个没有txt文件的空proguard文件夹，这是错误的吗？我检查了工作区，那里也是空的。
# This file is automatically generated by Android Tools.
# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
#
# This file must be checked in Version Control Systems.
#
# To customize properties used by the Ant build system edit
# "ant.properties", and override values to adapt the script to your
# project structure.
#
# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
proguard.config=${sdk.dir}/tools/proguard/proguard-android-optimize.txt:proguard-project.txt
# Project target.
target=android-19
android.library.reference.1=../appcompat_v7