downgraded mbed-client-c to work with nanostack

Author: Antti Kauppila

module.json

@@ -19,7 +19,7 @@
   ],
   "dependencies": {
     "nanostack-libservice": "^3.0.0",
-    "mbed-client-c": "^2.0.0",
+    "mbed-client-c": "^1.1.0",
     "sal-stack-nanostack": "^3.0.0",
     "mbedtls": "^2.0.0"
   },