liblog: always restore errno in logging functions

Some recent changes can have these logging functions potentially set
errno.  This change places android::base::ErrnoRestorer at the entry
point of the public functions where we want to guarantee errno is
restored to ensure this will not happen again.

Test: build
Change-Id: Iab4170ab16b9c7301474a509ee42d38b370b91a4
3 files changed