liblog: __android_log_is_loggable support Developer Options

- If logd.tag.<tag> is not found, check if persist.logd.tag.<tag> is available
- Do not turn off the isLoggable functionality on "user" builds

Bug: 19544788
Bug: 17760225
Change-Id: I3fec67b547aa431438965519507033798398e1e1
1 file changed