Workaround broken ipv6 site

This just forces wget to use ipv4 when downloading
more context here:
http://lists.freedesktop.org/archives/libreoffice/2015-October/070412.html

Change-Id: Id7e6a2ccd2301aa0fd1456d20309fe4936b4a20b
Reviewed-on: https://gerrit.libreoffice.org/19090Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>

Makefile.fetch

@@ -11,7 +11,7 @@ fetch_LOGFILE := $(TARFILE_LOCATION)/fetch.log
 
 ifneq (,$(WGET))
 define fetch_Download__wget_command
-&& $(WGET) --progress=dot:mega -Q 0 -P "." -l 0 -nd -nH -N $1/$2 2>&1 | tee -a $(fetch_LOGFILE) && [ $$PIPESTATUS -eq 0 ]
+&& $(WGET) --progress=dot:mega -4 -Q 0 -P "." -l 0 -nd -nH -N $1/$2 2>&1 | tee -a $(fetch_LOGFILE) && [ $$PIPESTATUS -eq 0 ]
 endef
 
 else