exempt a disk read from StrictMode as stetho is strictly a debug orie…

[jijichen]

Violation:

StrictMode policy violation; ~duration=5 ms: android.os.strictmode.DiskReadViolation
    at android.os.StrictMode$AndroidBlockGuardPolicy.onReadFromDisk(StrictMode.java:1596)
    at libcore.io.BlockGuardOs.fstat(BlockGuardOs.java:174)
    at libcore.io.ForwardingOs.fstat(ForwardingOs.java:106)
    at libcore.io.IoBridge.open(IoBridge.java:481)
    at java.io.FileInputStream.<init>(FileInputStream.java:160)
    at java.io.FileInputStream.<init>(FileInputStream.java:115)
    at com.facebook.stetho.common.ProcessUtil.readProcessName(ProcessUtil.java:49)
    at com.facebook.stetho.common.ProcessUtil.getProcessName(ProcessUtil.java:38)
    at com.facebook.stetho.server.AddressNameHelper.createCustomAddress(AddressNameHelper.java:20)
    at com.facebook.stetho.Stetho$Initializer.start(Stetho.java:449)
    at com.facebook.stetho.Stetho.initialize(Stetho.java:134)

But "/proc/self/cmdline is a memory file and won't actually hit disk"
thus it can be exempted.