Do not keep deprecated switches around

This is pretty bad idea, because when you really remove them it prints
nice warning, this way tho you have no damn chance to see it unless you
read the ./configure --help.

Change-Id: I2fc9ffc1dec4d69522e2a7c90cb5cf06f3d70c3d
Reviewed-on: https://gerrit.libreoffice.org/1271Reviewed-by: Tor Lillqvist <tml@iki.fi>
Tested-by: Tor Lillqvist <tml@iki.fi>

configure.ac

@@ -677,11 +677,6 @@ AC_ARG_ENABLE(vba,
         [Disables the vba compatibility feature.])
 )
 
-AC_ARG_ENABLE(pch,
-    AS_HELP_STRING([--enable-pch],
-        [DEPRECATED : is ignored])
-)
-
 AC_ARG_ENABLE(win-mozab-driver,
     AS_HELP_STRING([--enable-win-mozab-driver],
         [LibreOffice includes a driver to connect to Mozilla 
@@ -1245,11 +1240,6 @@ AC_ARG_WITH(system-nss,
         [Use NSS/nspr libraries already on system.]),,
     [with_system_nss="$with_system_libs"])
 
-AC_ARG_WITH(mozilla-toolkit,
-    AS_HELP_STRING([--with-mozilla-toolkit],
-        [DEPRECATED : is ignored]),
-,)
-
 AC_ARG_WITH(myspell-dicts,
     AS_HELP_STRING([--without-myspell-dicts],
         [Removes myspell dictionaries from LibreOffice installation set, for
@@ -1646,11 +1636,6 @@ AC_ARG_WITH(system-liblangtag,
         [Use liblangtag library already on system.]),,
     [with_system_liblangtag="$with_system_libs"])
 
-AC_ARG_WITH(system-mozilla,
-    AS_HELP_STRING([--with-system-mozilla],
-        [DEPRECATED : is ignored]),,
-)
-
 AC_ARG_WITH(system-npapi-headers,
     AS_HELP_STRING([--with-system-npapi-headers],
         [Use NPAPI headers provided by system instead of bundled ones. Used in