Revert "gnu: nmap: Update license."

This reverts commit 2323a7120a.
The new license has been deemed non-free by Fedora [1] and there has not yet
been a statement by the FSF claiming otherwise.  See also [2].

[1] https://github.com/nmap/nmap/issues/2199
[2] https://lists.gnu.org/archive/html/guix-devel/2020-10/msg00227.html

gnu/packages/admin.scm

@@ -2696,7 +2696,7 @@ advanced netcat implementation (ncat), a utility for comparing scan
 results (ndiff), and a packet generation and response analysis tool (nping).")
     ;; This package uses nmap's bundled versions of libdnet and liblinear, which
     ;; both use a 3-clause BSD license.
-    (license (list license:npsl license:bsd-3))))
+    (license (list license:nmap license:bsd-3))))
 
 (define-public dstat
   (package

guix/licenses.scm

@@ -78,7 +78,7 @@
             mpl1.0 mpl1.1 mpl2.0
             ms-pl
             ncsa
-            npsl
+            nmap
             ogl-psi1.0
             openldap2.8 openssl
             perl-license
@@ -531,10 +531,10 @@ at URI, which may be a file:// URI pointing the package's tree."
            "http://directory.fsf.org/wiki/License:IllinoisNCSA"
            "https://www.gnu.org/licenses/license-list#NCSA"))
 
-(define npsl
-  (license "Nmap Public Source License"
-           "https://svn.nmap.org/nmap/LICENSE"
-           "https://nmap.org/npsl/"))
+(define nmap
+  (license "Nmap license"
+           "https://svn.nmap.org/nmap/COPYING"
+           "https://fedoraproject.org/wiki/Licensing/Nmap"))
 
 (define ogl-psi1.0
   (license "Open Government Licence for Public Sector Information"