Contribs: don't hardcode URLs

contrib/src/jpeg/rules.mak

@@ -2,7 +2,7 @@
 
 JPEG_VERSION := 9a
 #JPEG_URL := http://www.ijg.org/files/jpegsrc.v$(JPEG_VERSION).tar.gz
-JPEG_URL := http://download.videolan.org/pub/contrib/jpegsrc.v$(JPEG_VERSION).tar.gz
+JPEG_URL := $(CONTRIB_VIDEOLAN)/jpegsrc.v$(JPEG_VERSION).tar.gz
 
 $(TARBALLS)/jpegsrc.v$(JPEG_VERSION).tar.gz:
 	$(call download,$(JPEG_URL))

contrib/src/live555/rules.mak

@@ -2,7 +2,7 @@
 
 #LIVEDOTCOM_URL := http://live555.com/liveMedia/public/live555-latest.tar.gz
 LIVE555_FILE := live.2014.07.25.tar.gz
-LIVEDOTCOM_URL := http://download.videolan.org/pub/contrib/live555/$(LIVE555_FILE)
+LIVEDOTCOM_URL := $(CONTRIB_VIDEOLAN)/live555/$(LIVE555_FILE)
 
 ifdef BUILD_NETWORK
 PKGS += live555

contrib/src/mpcdec/rules.mak

@@ -7,7 +7,7 @@ PKGS += mpcdec
 #MUSE_URL := http://files2.musepack.net/source/libmpcdec-$(MUSE_VERSION).tar.bz2
 
 MUSE_REV := 481
-MUSE_URL := http://download.videolan.org/pub/contrib/musepack_src_r$(MUSE_REV).tar.gz
+MUSE_URL := $(CONTRIB_VIDEOLAN)/musepack_src_r$(MUSE_REV).tar.gz
 
 $(TARBALLS)/musepack_src_r$(MUSE_REV).tar.gz:
 	$(call download,$(MUSE_URL))

contrib/src/orc/rules.mak

@@ -2,7 +2,7 @@
 
 ORC_VERSION := 0.4.18
 
-ORC_URL := http://download.videolan.org/pub/contrib/orc-$(ORC_VERSION).tar.gz
+ORC_URL := $(CONTRIB_VIDEOLAN)/orc-$(ORC_VERSION).tar.gz
 
 ifeq ($(call need_pkg,"orc-0.4"),)
 PKGS_FOUND += orc