libopenh264: bump to version 1.6.0

Contains a number of bugfixes, some of which may be security related:

http://www.openwall.com/lists/oss-security/2017/01/02/1

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libopenh264/libopenh264.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256 98077bd5d113c183ce02b678733b0cada2cf36750370579534c4d70f0b6c27b5  libopenh264-v1.5.0.tar.gz
+sha256 65d307bf312543ad6e98ec02abb7c27d8fd2c9740fd069d7249844612674a2c7  libopenh264-v1.6.0.tar.gz

package/libopenh264/libopenh264.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-LIBOPENH264_VERSION = v1.5.0
+LIBOPENH264_VERSION = v1.6.0
 LIBOPENH264_SITE = $(call github,cisco,openh264,$(LIBOPENH264_VERSION))
 LIBOPENH264_LICENSE = BSD-2c
 LIBOPENH264_LICENSE_FILES = LICENSE