设备：nexus 6
版本：Android 7.1.1
blockcanary版本：1.5.0
堆栈信息如下：
ava.io.FileNotFoundException: /data/storage/emulated/0/Android/data/com.test.testapm/cache/looper-2018-07-06_17-09-29.376.log (No such file or directory)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.(FileOutputStream.java:221)
at java.io.FileOutputStream.(FileOutputStream.java:140)
at com.github.moduth.blockcanary.LogWriter.save(LogWriter.java:108)
at com.github.moduth.blockcanary.LogWriter.save(LogWriter.java:56)
at com.github.moduth.blockcanary.BlockCanaryInternals$1.onBlockEvent(BlockCanaryInternals.java:63)
at com.github.moduth.blockcanary.LooperMonitor$1.run(LooperMonitor.java:80)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.os.HandlerThread.run(HandlerThread.java:61)
发现BlockCanaryInternals#getPath方法中，最后在目录前面加上了Data目录，导致目录生成失败。
markzhai
