Fix some warnings in Android libqi build.
Fix some warnings in Android libqi build.

Small optimizations in detail::log() implementation for Android.

Change-Id: Id5cc5640a33d1aa5c46535c83d70a9fcedc7b0bb
Reviewed-on: http://gerrit.aldebaran.lan/66868
Reviewed-by: icesi <89c787ac7bf5392f554c766f7de8c2903214fbf8@aldebaran.com>
Reviewed-by: jlamotte <70353e7b0c7d18b7fc75605daf0ccba69fcd3222@aldebaran.com>
Tested-by: icesi <89c787ac7bf5392f554c766f7de8c2903214fbf8@aldebaran.com>

aldebaran/libqi,aldebaran/libqi,aldebaran/libqi