opkg: bump to version 2017-07-28

Commits since last 2017-07-11:

4bd8601 pkg_parse: fix segfault when parsing descriptions with leading newlines

Fixes FS#933.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/system/opkg/Makefile

@@ -16,9 +16,9 @@ PKG_FLAGS:=essential
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=https://git.lede-project.org/project/opkg-lede.git
-PKG_SOURCE_DATE:=2017-07-11
-PKG_SOURCE_VERSION:=52fc0069b50b9be89ae3b525b98741123461dd0a
-PKG_MIRROR_HASH:=f7b0ea689b6e3f1cf680514bd59b13d9cd33c8255056b49af85e512554f97ccf
+PKG_SOURCE_DATE:=2017-07-28
+PKG_SOURCE_VERSION:=4bd8601ebd95c130e504cc724b0c5eb163050982
+PKG_MIRROR_HASH:=adb2d610185a83fb630ccd3f0c80cb8acfd89260e0a5e598aadb8c8f0d903cf5
 
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=COPYING