Install libgcrypt on osx travis

travis-dependencies.sh

@@ -2,7 +2,7 @@
 
 if [[ $TRAVIS_OS_NAME == "osx" ]] ; then
   brew update
-  brew install qt cmake protobuf
+  brew install qt cmake protobuf libgcrypt
 else
   sudo apt-get update -qq
   sudo apt-get install -y qtmobility-dev libprotobuf-dev protobuf-compiler libqt4-dev