build: remove cares headers from tarball

The bundled c-ares isn't very suitable for consumption by addons,
isn't kept stable, and isn't exported on windows.

PR-URL: nodejs#10283
Refs: nodejs/node-gyp#1055
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

tools/install.py

@@ -159,9 +159,6 @@ def headers(action):
 
   subdir_files('deps/v8/include', 'include/node/', action)
 
-  if 'false' == variables.get('node_shared_cares'):
-    subdir_files('deps/cares/include', 'include/node/', action)
-
   if 'false' == variables.get('node_shared_libuv'):
     subdir_files('deps/uv/include', 'include/node/', action)