当项目加入sinaSDK后，混淆项目时，虽然已经写了：
-dontwarn com.weibo.sdk.android.**
但是仍然无法发布成功，会出现如下错误：
Proguard returned with error code 1. See console
Note: there were 1 duplicate class definitions.
Warning: library class android.webkit.WebViewClient depends on program class android.net.http.SslError
Warning: there were 1 instances of library classes depending on program classes.
You must avoid such dependencies, since the program classes will
be processed, while the library classes will remain unchanged.
java.io.IOException: Please correct the above warnings first.
at proguard.Initializer.execute(Initializer.java:321)
at proguard.ProGuard.initialize(ProGuard.java:211)
at proguard.ProGuard.execute(ProGuard.java:86)
at proguard.ProGuard.main(ProGuard.java:492)
根据异常相信同行们已经看出来了，还要单独keep 一下SslError这个，因为这个东西没有在 com.weibo.sdk.android这个包里面，于是再加上：
-dontwarn android.net.http.**
这样就解决问题了。