fix travis ci config

.travis.yml

@@ -4,7 +4,10 @@ language: cpp
 compiler: gcc
 
 install:
-  - sudo apt-get install lcov libcurl4-openssl-dev libssl-dev uuid-dev libjsoncpp-dev nodejs npm
+  - sudo apt-get install lcov libcurl4-openssl-dev libssl-dev uuid-dev libjson-c-dev libjsoncpp-dev nodejs npm
+
+env:
+  - CPLUS_INCLUDE_PATH="/usr/local/include/:/usr/include/jsoncpp/:/usr/local/opt/openssl/include/:/usr/lib/"
 
 script:
   - ./unit_test.sh