Remove ZPL from LICENSES.txt

The last piece of ZPL code was "trackrefs.py", which was removed in
6c1c0ad.  The notice removed in this
commit says ZPL code is identified in the file header.  The commands
"grep -ri zope *" and "grep -ri zpl *" do not find any more code files.

LICENSES.txt

@@ -87,7 +87,7 @@ Rushing:
   server, ftp server, utilities, etc.  Medusa is therefore under the
   following license:
 
-  ============================== 
+  ==============================
   Permission to use, copy, modify, and distribute this software and
   its documentation for any purpose and without fee is hereby granted,
   provided that the above copyright notice appear in all copies and
@@ -104,61 +104,3 @@ Rushing:
   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
   WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   ==============================
-
-Some software in this distribution is released under the Zope Public
-License (as marked in its file header):
-
-  Zope Public License (ZPL) Version 2.1
-  -------------------------------------
-
-  A copyright notice accompanies this license document that
-  identifies the copyright holders.
-
-  This license has been certified as open source. It has also
-  been designated as GPL compatible by the Free Software
-  Foundation (FSF).
-
-  Redistribution and use in source and binary forms, with or
-  without modification, are permitted provided that the
-  following conditions are met:
-
-  1. Redistributions in source code must retain the
-     accompanying copyright notice, this list of conditions,
-     and the following disclaimer.
-
-  2. Redistributions in binary form must reproduce the accompanying
-     copyright notice, this list of conditions, and the
-     following disclaimer in the documentation and/or other
-     materials provided with the distribution.
-
-  3. Names of the copyright holders must not be used to
-     endorse or promote products derived from this software
-     without prior written permission from the copyright
-     holders.
-
-  4. The right to distribute this software or to use it for
-     any purpose does not give you the right to use
-     Servicemarks (sm) or Trademarks (tm) of the copyright
-     holders. Use of them is covered by separate agreement
-     with the copyright holders.
-
-  5. If any files are modified, you must cause the modified
-     files to carry prominent notices stating that you changed
-     the files and the date of any change.
-
-  Disclaimer
-
-    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS''
-    AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
-    NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
-    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
-    NO EVENT SHALL THE COPYRIGHT HOLDERS BE
-    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
-    OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
-    DAMAGE.