remove extraneous `using namespace android` and deprecate utils/Log.h

This namespace is not used by this file and its declaration is removed
in a separate CL from utils/Log.h, which is the only place it is
defined, so we must remove this extraneous line.

Also, since that separate CL is deprecating utils/Log.h in favor of
log/log.h, we make the switch to the new header.

Test: Build
Exempt-From-Owner-Approval: Owners file needs updating
Change-Id: I34aa80765d30c79f8cb67eaf95a9995066bd672e