[API CHANGE] Remove unused StartCenterHideExternalLinks configuration property

Originally added with 78e8d5f0 "Added option to
hide external link buttons on Start Center".

The use of BackingWindow::mnHideExternalLinks was remove with
74144e53 "startcenter: Tweak Start Center
layout", and then the member and its initialization from the
StartCenterHideExternalLinks configuration property was removed with
d7824bf1 "loplugin:unusedfields in sfx2 part2".

(The opportunity to already remove STARTCENTER_HIDE_EXTERNAL_LINKS from
instsetoo_native/util/openoffice.lst.in had been missed in
89ac3c4a "replace variables in main.xcd already
in gbuild".)

Change-Id: I35bbd94db88939d7724616fa22a74e18552a4ad8
Reviewed-on: https://gerrit.libreoffice.org/55379Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

instsetoo_native/util/openoffice.lst.in

@@ -32,7 +32,6 @@ Globals
             PACKAGEMAP package_names.txt,package_names_ext.txt
             WINDOWSPATCHLEVEL 8
             OOODOWNLOADNAME 1
-            STARTCENTER_HIDE_EXTERNAL_LINKS 0
             64BITPRODUCT @WINDOWS_X64@
             WINDOWSSDKVERSION @WINDOWS_SDK_VERSION@
         }
@@ -72,7 +71,6 @@ LibreOffice
             STARTCENTER_INFO_URL https://www.libreoffice.org/
             STARTCENTER_TEMPLREP_URL https://templates.libreoffice.org/
             DICT_REPO_URL https://extensions.libreoffice.org/dictionaries/
-            STARTCENTER_HIDE_EXTERNAL_LINKS 0
         }
         active          1
         compression     5
@@ -125,7 +123,6 @@ LibreOfficeDev
             STARTCENTER_INFO_URL https://www.libreoffice.org/
             STARTCENTER_TEMPLREP_URL https://templates.libreoffice.org/
             DICT_REPO_URL https://extensions.libreoffice.org/dictionaries/
-            STARTCENTER_HIDE_EXTERNAL_LINKS 0
         }
         active          1
         compression     5
@@ -167,7 +164,6 @@ LibreOffice_SDK
             STARTCENTER_INFO_URL https://www.libreoffice.org/
             STARTCENTER_TEMPLREP_URL https://templates.libreoffice.org/
             DICT_REPO_URL https://extensions.libreoffice.org/dictionaries/
-            STARTCENTER_HIDE_EXTERNAL_LINKS 0
         }
         active 1
         compression 5
@@ -213,7 +209,6 @@ LibreOfficeDev_SDK
             STARTCENTER_INFO_URL https://www.libreoffice.org/
             STARTCENTER_TEMPLREP_URL https://templates.libreoffice.org/
             DICT_REPO_URL https://extensions.libreoffice.org/dictionaries/
-            STARTCENTER_HIDE_EXTERNAL_LINKS 0
         }
         active 1
         compression 5

officecfg/registry/data/org/openoffice/Office/Common.xcu

@@ -42,9 +42,6 @@
       <prop oor:name="TemplateRepositoryURL" oor:type="xs:string">
         <value>${STARTCENTER_TEMPLREP_URL}</value>
       </prop>
-      <prop oor:name="StartCenterHideExternalLinks" oor:type="xs:int">
-        <value>${STARTCENTER_HIDE_EXTERNAL_LINKS}</value>
-      </prop>
     </node>
     <prop oor:name="System">
       <value install:module="unx">UNIX</value>

officecfg/registry/schema/org/openoffice/Office/Common.xcs

@@ -3586,13 +3586,6 @@
           </info>
           <value/>
         </prop>
-        <prop oor:name="StartCenterHideExternalLinks" oor:type="xs:int" oor:nillable="false">
-          <info>
-            <desc>Contains a number deciding whether to show or hide buttons
-            with external links</desc>
-          </info>
-          <value>0</value>
-        </prop>
         <prop oor:name="StartCenterBackgroundColor" oor:type="xs:int" oor:nillable="false">
           <!-- Default 14540253 = 0xdddddd as specified in tdf#90452, comment 45 -->
           <info>

postprocess/CustomTarget_registry.mk

@@ -554,7 +554,6 @@ postprocess_main_SED := \
 	-e 's,$${PRODUCTEXTENSION},.$(LIBO_VERSION_MICRO).$(LIBO_VERSION_PATCH)$(LIBO_VERSION_SUFFIX),g' \
 	-e 's,$${STARTCENTER_ADDFEATURE_URL},http://extensions.libreoffice.org/,g' \
 	-e 's,$${STARTCENTER_INFO_URL},https://www.libreoffice.org/,g' \
-	-e 's,$${STARTCENTER_HIDE_EXTERNAL_LINKS},0,g' \
 	-e 's,$${STARTCENTER_TEMPLREP_URL},http://templates.libreoffice.org/,g' \
 	-e 's,$${SYSTEM_LIBEXTTEXTCAT_DATA},$(SYSTEM_LIBEXTTEXTCAT_DATA),g' \
 	-e 's,$${SYSTEM_LIBNUMBERTEXT_DATA},$(SYSTEM_LIBNUMBERTEXT_DATA),g' \