package/cjson: bump to version 1.7.15

Fixes:
- Fix potential core dumped for strrchr
- Fix null pointer crash in cJSON_CreateXxArray
- Fix several null pointer problems on allocation failure
- Fix a possible dereference of null pointer

https://github.com/DaveGamble/cJSON/releases/tag/v1.7.15

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/cjson/cjson.hash

@@ -1,3 +1,3 @@
 # Locally computed:
-sha256  fb50a663eefdc76bafa80c82bc045af13b1363e8f45cec8b442007aef6a41343  cjson-1.7.14.tar.gz
+sha256  5308fd4bd90cef7aa060558514de6a1a4a0819974a26e6ed13973c5f624c24b2  cjson-1.7.15.tar.gz
 sha256  a36dda207c36db5818729c54e7ad4e8b0c6fba847491ba64f372c1a2037b6d5c  LICENSE

package/cjson/cjson.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-CJSON_VERSION = 1.7.14
+CJSON_VERSION = 1.7.15
 CJSON_SITE = $(call github,DaveGamble,cjson,v$(CJSON_VERSION))
 CJSON_INSTALL_STAGING = YES
 CJSON_LICENSE = MIT