THRIFT-3816 Reduce docker build duration on Travis-CI

This closes #1007
diff --git a/.travis.yml b/.travis.yml
index 33a32d8..f8a8c1e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -26,12 +26,11 @@
   - docker
 
 install:
-  - travis_wait docker pull thrift/$DISTRO:latest || true
   - cp -r ./build/docker/scripts/*.sh ./build/docker/$DISTRO/scripts/
   - travis_retry travis_wait docker build -q -t thrift-build build/docker/$DISTRO
 
 script:
-  - docker run -e BUILD_LIBS="$BUILD_LIBS" $BUILD_ENV -v $(pwd):/thrift/src -it thrift-build $BUILD_CMD $BUILD_ARG
+  - docker run --net=host -e BUILD_LIBS="$BUILD_LIBS" $BUILD_ENV -v $(pwd):/thrift/src -it thrift-build $BUILD_CMD $BUILD_ARG
 
 env:
   global: