build/linux: properly set build args

.travis.yml

@@ -17,7 +17,7 @@ env:
 
 script:
   - git submodule update --init
-  - curl -O -L https://github.com/grammarly/rocker/releases/download/1.3.0/rocker_linux_amd64.tar.gz
+  - curl -O -L https://github.com/Hellslicer/rocker/releases/download/1.3.4/rocker_linux_amd64.tar.gz
   - tar xvf rocker_linux_amd64.tar.gz
   - cd code/
   - 'if [ -z "$TRAVIS_TAG" ]; then ../rocker build --build-arg JOB_SLOTS=$(nproc); fi'

code/Rockerfile

@@ -1,22 +1,15 @@
-# environment variables workaround
-FROM alpine:3.8
-ARG CI_BRANCH
-ARG CI_BUILD_NUMBER
-ARG JOB_SLOTS
-MOUNT ..:/src
-RUN echo 'export CI_BRANCH='$CI_BRANCH > /src/.env
-RUN echo 'export CI_BUILD_NUMBER='$CI_BUILD_NUMBER >> /src/.env
-RUN echo 'export JOB_SLOTS='$JOB_SLOTS >> /src/.env
-
 # build system resources
 FROM mcr.microsoft.com/dotnet/core/sdk:2.2-alpine3.9
 MOUNT ..:/src
 RUN cd /src/ext/system-resources/ && /bin/sh build.sh
 
 # build server
 FROM alpine:3.8
+ARG CI_BRANCH
+ARG CI_BUILD_NUMBER
+ARG JOB_SLOTS
 MOUNT ..:/src
-RUN source /src/.env && /bin/sh /src/code/tools/ci/build_server_2.sh
+RUN /bin/sh /src/code/tools/ci/build_server_2.sh
 RUN mkdir -p /opt/cfx-server/citizen/system_resources/
 RUN cp -a /src/ext/system-resources/data/* /opt/cfx-server/citizen/system_resources/
 ENV LD_LIBRARY_PATH /usr/lib/v8/:/lib:/usr/lib/