Install protobuf-c-compiler

Author: mbinna

.travis.yml

@@ -5,7 +5,7 @@ compiler:
     - gcc
 before_install:
     - sudo apt-get -qq update
-    - sudo apt-get install -y cmake protobuf
+    - sudo apt-get install -y cmake protobuf-c-compiler
 script:
     - mkdir build
     - cd build