package/musepack: use version friendly to release-monitoring

Update MUSEPACK_VERSION to match what is returned by
https://release-monitoring.org/project/21865

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/musepack/musepack.mk

@@ -4,9 +4,9 @@
 #
 ################################################################################
 
-MUSEPACK_VERSION = r475
+MUSEPACK_VERSION = 475
 MUSEPACK_SITE = http://files.musepack.net/source
-MUSEPACK_SOURCE = musepack_src_$(MUSEPACK_VERSION).tar.gz
+MUSEPACK_SOURCE = musepack_src_r$(MUSEPACK_VERSION).tar.gz
 MUSEPACK_DEPENDENCIES = libcuefile libreplaygain
 MUSEPACK_INSTALL_STAGING = YES
 MUSEPACK_BUILD_OPTS = -j1