Revert "Modularize logd."

logd isn't meant to be modularized.  The previous user was using a
small subset of LogListener.cpp, which is now copied into their
project.

Test: liblog, logd unit tests

This reverts commit fafea324.

Change-Id: I05ec764db2d9395f2d5b69a1a610c9c55240ab3a