Fix file permissions of generated layers trace

Fix: 305129514
Test: adb shell rm /data/misc/wmtrace/layers_trace_from_transactions.winscope \
    && adb bugreport \
    && check generated bugreport contains FS/data/misc/wmtrace/layers_trace_from_transactions.winscope
Change-Id: I7cf087265df9ce1cc5da8536d6b03285685cd26e
1 file changed