contrib: use jsoncpp 1.7.2 on GNU/Linux

jsoncpp-devel is broken since some versions
Will be fixed by: https://github.com/open-source-parsers/jsoncpp/pull/1236

Change-Id: I3ab8eaffcb6abcd28f06aaeeba8f57131fb97af8

contrib/src/jsoncpp/SHA512SUMS

-f1c035d54ed952d8d4e41acab5c3ecf6aa445f348f98aeac2e7c89555ec2f6421d727b3bc4c2f54176afce137c545b20d886562901953ec091f91890e91e8559  jsoncpp-1.9.3.tar.gz
+32702147229ea7a3679654325572c38f4188f258ab6ac21f9e04059d53ef2a7cd0542ec4ec3b0e7b9089acd2b7bce389f16b9ff24b2e63e0ba2a5bcd46bab766  jsoncpp-1.7.2.tar.gz
+f1c035d54ed952d8d4e41acab5c3ecf6aa445f348f98aeac2e7c89555ec2f6421d727b3bc4c2f54176afce137c545b20d886562901953ec091f91890e91e8559  jsoncpp-1.9.3.tar.gz
\ No newline at end of file

contrib/src/jsoncpp/rules.mak

 # JSONCPP
+ifdef HAVE_LINUX
+JSONCPP_VERSION := 1.7.2
+else
 JSONCPP_VERSION := 1.9.3
+endif
 JSONCPP_URL := https://github.com/open-source-parsers/jsoncpp/archive/$(JSONCPP_VERSION).tar.gz
 
 PKGS += jsoncpp