fix tests: add USE_BROTLI in relevant Dockerfiles

search for Dockerfiles that run 'make [some_walg_build_rule]' at
docker build time, and set "ENV USE_BROTLI 1" in those Dockerfiles

docker/fdb_tests/Dockerfile

@@ -13,6 +13,7 @@ COPY cmd/ cmd/
 COPY main/ main/
 COPY utility/ utility/
 COPY Makefile Makefile
+ENV USE_BROTLI 1
 
 RUN sed -i 's|#cgo LDFLAGS: -lbrotli.*|&-static -lbrotlicommon-static -lm|' \
         vendor/github.com/google/brotli/go/cbrotli/cgo.go && \

docker/gp_tests/Dockerfile

@@ -13,7 +13,7 @@ COPY cmd/ cmd/
 COPY main/ main/
 COPY utility/ utility/
 COPY Makefile Makefile
-
+ENV USE_BROTLI 1
 
 RUN sed -i 's|#cgo LDFLAGS: -lbrotli.*|&-static -lbrotlicommon-static -lm|' \
         vendor/github.com/google/brotli/go/cbrotli/cgo.go && \

tests_func/Dockerfile.mongodb

@@ -11,6 +11,7 @@ ARG MONGO_VERSION=
 ARG MONGO_TOOLS_VERSION=100.4.0
 ENV TMP_DIR /var/tmp/wal-g
 ENV WALG_CONF_DIR /etc/wal-g/
+ENV USE_BROTLI 1
 
 RUN echo "deb http://$MONGO_REPO/apt/ubuntu bionic/${MONGO_PACKAGE}/${MONGO_MAJOR} multiverse" | tee "/etc/apt/sources.list.d/mongodb_${MONGO_MAJOR}.list" && \
     wget -qO - https://www.mongodb.org/static/pgp/server-${MONGO_MAJOR}.asc | apt-key add -
@@ -48,6 +49,7 @@ COPY staging/wal-g ${WALG_REPO}/
 
 WORKDIR ${WALG_REPO}
 
+
 RUN make link_external_deps
 RUN make BUILD_ARGS=-race mongo_build && \
     cp main/mongo/wal-g /usr/bin/wal-g

tests_func/Dockerfile.redis

@@ -12,6 +12,7 @@ ENV USER redis
 ENV GROUP redis
 ENV USERGROUP $USER:$GROUP
 ENV HOME /home/$USER
+ENV USE_BROTLI 1
 
 # add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
 RUN groupadd -r -g 999 $USER && useradd -r -g $GROUP -u 999 $USER