docs: delete certificate spec
Moved to the NDN-packet-spec repo
https://github.com/named-data/NDN-packet-spec/commit/3a74e134979606af9a2b90b12f141f8794ad96d7
Change-Id: I57aec08aeb553d5eb6c5a7c368ba03b904b1e4ed
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index dd394ec..30dadaf 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -192,7 +192,7 @@
package is installed and ``PKG_CONFIG_PATH`` is configured properly (or if
``<LIBPATH>/pkgconfig`` is a default search path), the command ``pkg-config --cflags
--libs libndn-cxx`` will return all necessary compile and link flags for the library.
-- ``<BINPATH>/ndnsec``: tool to manage NDN keys and certificates.
+- ``<BINPATH>/ndnsec``: command-line tool to manage NDN keys and certificates.
- ``<BINPATH>/ndnsec-*``: convenience aliases for ``ndnsec`` tools.
If configured with tests (``./waf configure --with-tests``), the above commands