Translation: Drop deprecated language links (squid-cache#1643)

Support for full-name languages has been deprecated since
Squid-3.1 it is long overdue to remove these symlinks and
simplify the default install footprint.

doc/release-notes/release-7.sgml.in

@@ -32,6 +32,7 @@ The Squid-@SQUID_RELEASE@ change history can be <url url="https://github.com/squ
 <itemize>
 	<item>Cache Manager changes
 	<item>Removed purge tool
+	<item>Remove deprecated languages
 </itemize>
 
 <p>Most user-facing changes are reflected in squid.conf (see further below).
@@ -82,6 +83,26 @@ The Squid-@SQUID_RELEASE@ change history can be <url url="https://github.com/squ
 </verb>
    Alternatively the HTCP <em>CLR</em> mechanism can be used.
 
+<sect1>Removed deprecated languages
+<p>Old Squid used full language name to refer to error page translations.
+   These have been deprecated since addition of ISO-639 language codes
+   and support for HTTP Accept-Language negotiation in Squid-3.x.
+
+<p>As of this release Squid will no longer provide the symlinks
+   needed for seamless upgrade for squid.conf containing settings such as
+<verb>
+    error_directory English
+</verb>
+   All Squid installations are expected to already have them,
+   or to convert to the ISO-639 equivalents. Existing symlinks are not
+   affected.
+
+<p>See <url url="http://www.squid-cache.org/Versions/langpack/"> for the latest
+   list of official Squid translations.
+
+<p>See <url url="https://en.wikipedia.org/wiki/List_of_ISO_639_language_codes"> for
+   the full ISO-639 list. HTTP uses the 2-letter (set 1) codes.
+
 
 <sect>Changes to squid.conf since Squid-@SQUID_RELEASE_OLD@
 <p>

errors/Makefile.am

@@ -28,7 +28,7 @@ EXTRA_DIST = \
 	templates/error-details.txt \
 	language.am \
 	template.am \
-	aliases alias-link.sh alias-upgrade errorpage.css TRANSLATORS COPYRIGHT
+	aliases alias-link.sh errorpage.css TRANSLATORS COPYRIGHT
 
 if ENABLE_TRANSLATION
 ALIAS_LINKER=$(SHELL) $(srcdir)/alias-link.sh "$(LN)" "$(RM)" "$(DESTDIR)$(DEFAULT_ERROR_DIR)"
@@ -126,10 +126,6 @@ uninstall-local:
 	rm -f $(DESTDIR)$(DEFAULT_ERROR_DIR)/TRANSLATORS
 	rm -f $(DESTDIR)$(DEFAULT_ERROR_DIR)/COPYRIGHT
 
-## Upgrade requires the new files to be pre-installed
-upgrade: install
-	$(ALIAS_LINKER) "$(srcdir)/alias-upgrade" || exit 1 ;
-
 dist-hook: translate
 	for lang in $(TRANSLATE_LANGUAGES); do \
 	  lang=`basename $$lang .lang`; \