Removed documentation on false paths as per #2083 (#2146)

Removed documentation on false paths as per #2083

lib/spack/docs/configuration.rst

@@ -134,34 +134,6 @@ buggy or otherwise undesirable.
 
 .. _system-packages:
 
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-False Paths for System Packages
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Sometimes, the externally-installed package one wishes to use with
-Spack comes with the Operating System and is installed in a standard
-place --- ``/usr``, for example.  Many other packages are there as
-well.  If Spack adds it to build paths, then some packages might
-pick up dependencies from ``/usr`` than the intended Spack version.
-
-In order to avoid this problem, it is advisable to specify a fake path
-in ``packages.yaml``, thereby preventing Spack from adding the real
-path to compiler command lines.  This will work because compilers
-normally search standard system paths, even if they are not on the
-command line.  For example:
-
-.. code-block:: yaml
-
-    packages:
-        # Recommended for security reasons
-        # Do not install OpenSSL as non-root user.
-        openssl:
-            paths:
-                openssl@system: /false/path
-            version: [system]
-            buildable: False
-
-
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 Extracting System Packages
 ^^^^^^^^^^^^^^^^^^^^^^^^^^

lib/spack/docs/getting_started.rst

@@ -730,21 +730,10 @@ there."  This is reasonable for OpenSSL, which has a stable API.
     packages:
         openssl:
             paths:
-                openssl@system: /false/path
+                openssl@system: /usr
             version: [system]
             buildable: False
 
-.. note::
-
-   Even though OpenSSL is located in ``/usr``, We have told Spack to
-   look for it in ``/false/path``.  This prevents ``/usr`` from being
-   added to compilation paths and RPATHs, where it could cause
-   unrelated system libraries to be used instead of their Spack
-   equivalents.
-
-   The adding of ``/usr`` to ``RPATH`` in this sitution is a known issue
-   and will be fixed in a future release.
-
 
 ^^^^^^^^^^^^^
 BLAS / LAPACK