[github39] Reverted DocBook 5.0 reference in manpages. They look ok again

src/bin/admin/kea-admin.xml

@@ -7,7 +7,7 @@
 -->
 
 <!-- Converted by db4-upgrade version 1.1 -->
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
   <info>
     <productname>ISC Kea</productname>
     <date>Sep. 28, 2016</date>

src/bin/agent/kea-ctrl-agent.xml

@@ -7,7 +7,7 @@
 -->
 
 <!-- Converted by db4-upgrade version 1.1 -->
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <info>
     <productname>ISC Kea</productname>

src/bin/d2/kea-dhcp-ddns.xml

@@ -6,7 +6,7 @@
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
 <!-- Converted by db4-upgrade version 1.1 -->
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <info>
     <productname>ISC Kea</productname>

src/bin/dhcp4/kea-dhcp4.xml

@@ -6,7 +6,7 @@
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
 <!-- Converted by db4-upgrade version 1.1 -->
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <info>
     <productname>ISC Kea</productname>

src/bin/dhcp6/kea-dhcp6.xml

@@ -5,7 +5,7 @@
  - License, v. 2.0. If a copy of the MPL was not distributed with this
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <info>
     <productname>ISC Kea</productname>

src/bin/keactrl/keactrl.xml

@@ -6,7 +6,7 @@
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
 
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
   <info>
     <productname>ISC Kea</productname>
     <date>Oct. 27, 2017</date>

src/bin/lfc/kea-lfc.xml

@@ -7,7 +7,7 @@
 -->
 
 <!-- Converted by db4-upgrade version 1.1 -->
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <info>
     <productname>ISC Kea</productname>

src/bin/perfdhcp/perfdhcp.xml

@@ -6,7 +6,7 @@
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
 
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
     <info>
       <productname>ISC Kea</productname>

src/bin/shell/kea-shell.xml

@@ -6,7 +6,7 @@
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
 
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <info>
     <productname>ISC Kea</productname>

src/bin/sockcreator/kea-sockcreator.xml

@@ -6,7 +6,7 @@
  - file, You can obtain one at http://mozilla.org/MPL/2.0/.
 -->
 
-<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
+<refentry>
 
   <refentryinfo>
     <productname>ISC Kea</productname>