logd: remove users of __android_logger_property_get_bool()

__android_logger_property_get_bool() has a clunky API and doesn't
belong in liblog, since a vast majority of liblog users will never
query this property.

Specifically
1) Replace with GetBoolProperty() when completely equivalent.
2) Remove checking if property values are 'eng' or 'svelte', since
   there's no evidence that those values were ever used.
3) Remove checking 'persist.logd.statistics' and 'ro.logd.statistics',
   since there's no evidence that those values were ever used.
4) Set ro.logd.kernel explicitly, so other processes don't need to
   replicate the defaults that logd uses.

Test: build
Change-Id: I7c37af64ba7754e839185f46da66bf077f09d9c3