Enable tempest install to setup a config dir

This commit adds the necessary bits to tempest's setup.cfg file to
instruct pbr on how to make sure that the sample config files and
a /etc/tempest dir get setup when installing tempest. In the new
cli workflow it is expected that by default /etc/tempest will exist
as a source for local working dir configs.

Partially implements: bp tempest-cli-improvements

Change-Id: I2bf93f6789601caaebdfb85ac2b9f34b82f87980
diff --git a/setup.cfg b/setup.cfg
index 5c78632..36b2270 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -18,6 +18,12 @@
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.4
 
+[files]
+packages =
+    tempest
+data_files =
+    /etc/tempest = etc/*
+
 [entry_points]
 console_scripts =
     verify-tempest-config = tempest.cmd.verify_tempest_config:main