Drop rbczmq from docker config

Author: rstammer

ci/Dockerfile.main.erb

@@ -1,8 +1,6 @@
 FROM iruby-test-base:ruby-<%= ruby_version %>
 
-RUN gem install cztop \
-    && gem install rbczmq -- --with-system-libs
-
+RUN gem install cztop
 RUN mkdir -p /iruby
 ADD . /iruby
 WORKDIR /iruby

run-test.sh

@@ -4,7 +4,7 @@ set -ex
 
 export PYTHON=python3
 
-ADAPTERS="cztop rbczmq ffi-rzmq pyzmq"
+ADAPTERS="cztop ffi-rzmq pyzmq"
 
 for adapter in $ADAPTERS; do
   export IRUBY_TEST_SESSION_ADAPTER_NAME=$adapter