Upgrade to use rc5 of libpng1.26 this includes the security fixes

and also bugfixes to bugs that were introduced by rc1.
This fixes various segfaults of Opie applications on start up
due broken libpng

BKrev: 411e8329vcagNSNFoddMDBX6wYfc9Q

diff --git a/libpng/libpng-native_1.2.5+1.2.6rc1.oe b/libpng/libpng-native_1.2.5+1.2.6rc5.oe
similarity index 100%
rename from libpng/libpng-native_1.2.5+1.2.6rc1.oe
rename to libpng/libpng-native_1.2.5+1.2.6rc5.oe

diff --git a/libpng/libpng_1.2.5+1.2.6rc1.oe b/libpng/libpng_1.2.5+1.2.6rc5.oe
similarity index 100%
rename from libpng/libpng_1.2.5+1.2.6rc1.oe
rename to libpng/libpng_1.2.5+1.2.6rc5.oe