package/pcre: fix broken URL

As stated on www.pcre.org:
"Note that the former ftp.pcre.org FTP site is no longer available."

Update _SITE URL to Sourceforge.

Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 236385c50f58190f0dafb342d1d6c5115068683e)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/pcre/pcre.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 PCRE_VERSION = 8.44
-PCRE_SITE = https://ftp.pcre.org/pub/pcre
+PCRE_SITE = http://downloads.sourceforge.net/project/pcre/pcre/$(PCRE_VERSION)
 PCRE_SOURCE = pcre-$(PCRE_VERSION).tar.bz2
 PCRE_LICENSE = BSD-3-Clause
 PCRE_LICENSE_FILES = LICENCE