simplify coverage config

I *think* we don't need to tell .coverage to look in lib,
it seems to be covering from whereever successfuly.  not
sure, but want to run on jenkins to see how it comes out.

Change-Id: Ib74f427a5b09fcbeba0188dcf02dab27c329a8cd

Author: zzzeek

.coveragerc

@@ -3,11 +3,6 @@
 envlist = py
 
 [testenv]
-# note that we have a .coveragerc file that points coverage specifically
-# at ./lib/sqlalchemy, and *not* at the build that tox might create under .tox.
-# See the notes below for setenv for more detail.
-# also using --cov-append so that we can aggregate multiple runs together.
-# Jenkins etc. need to call "coverage erase" externally.
 cov_args=--cov=sqlalchemy --cov-report term --cov-append --cov-report xml --exclude-tag memory-intensive --exclude-tag timing-intensive -k "not aaa_profiling"
 
 install_command=python -m pip install {env:TOX_PIP_OPTS:} {opts} {packages}